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The house or typhoid fly, Musca domestica. Greatly enlarged. (Howard and Pierce, 

photo by Dovener.) 



SANITARY 
ENTOMOLOGY 


THE ENTOMOLOGY OF DISEASE, 
HYGIENE AND SANITATION 


EDITED ] 

WILLIAM DWIGHT 

Consulting Entomologist, formerly Erik 

Insect Investigations United 

of Agriculture, Bureau 


3Y 

PIERCE, Ph.D. 

ymologist Southern Field Crop 
States Department 
of Entomology 


ff\f. ARTI Ct V6RITATI HI 


BOSTON 

RICHARD G. BADGER 

THE GORHAM PRESS 



Copyright, 1921, by Richard G. Badger 
All Rights Reserved 






m 10 192! 

Made in the United States of America 



The Gorham Press, Boston, U. S. A. 



©CU608637 






TO 
Dr. LELAND OSSIAN HOWARD 

Chief of the Bureau of Entomology, 

this book is 
DEDICATED 

TO HIM, MORE THAN TO ANY ONE ELSE, DO ENTOMOLOGISTS OWE 
THE PRACTICAL DEVELOPMENT OF THEIR SCIENCE, WHICH 
TOUCHES UPON EVERY HUMAN ACTIVITY. HE STOOD AMONG 
THE FIRST TO EMPHASIZE THE IMPORTANCE OF SANITARY 
ENTOMOLOGY. HE STANDS NOW THE CHIEF EXPONENT OF 
ENTOMOLOGY THROUGHOUT THE WORLD. 



FOREWORD 

In May, 1918, a class was formed among the entomologists of the 
country to study the recent developments in the entomology of disease, 
hygiene, and sanitation, for the purpose of equipping themselves for any 
special service which they might be called upon to render during the war. 
The lectures were mimeographed week by week and mailed to the enrolled 
membership, which numbered in excess of 500. 

The war emergency is over and the mimeographed lectures have 
practically all been distributed. These lectures, however, dealt as much 
with domestic as with military problems, and they have now been com- 
pletely revised up to date of March 1, 1919, and are given forth as a 
series of lectures dealing with the entomological problems of peace times 
from the standpoint primarily of municipal, industrial, and household 
problems, and also with the hope that the course will be of assistance to 
teachers, and will stimulate research among investigators. Many 
important topics have been omitted, for we cannot hope to present the 
whole subject in a book of this size. 

This phase of entomology is one which is destined to become very 
important as our knowledge of disease transmission increases. There 
are many unworked and insufficiently worked problems now in sight, and 
these lectures will be found to suggest numerous possible lines of research. 

I wish at this time to express my appreciation of the services of 
Mr. Jacob Kotinsky, who served as Secretary of the Class, and of my 
collaborators in this course of lectures. 

As nearly as possible the International Rules of Nomenclature are 
followed, but in Entomology the practice had not been followed of en- 
closing the original author's name in parenthesis followed by the name 
of the author responsible for the present combination, and it has been 
impossible in the present volume to obtain all of the necessary information. 

W. Dwight Pierce. 



CONTENTS 



TEB PAGE 

I. How Insects Can Carry or Cause Disease 19 

Classification of Methods by Which Insects Can Carry or Cause 

Disease 20 

Why it is Necessary to Know How Insects Carry Disease ... 23 

II. Some Necessary Steps in Any Attempt to Prove Insect Transmission or 

Causation of Disease 25 

I. Cooperation 25 

II. Where Should the Investigations of Insect Transmission Begin? 26 

III. Flan of Operation 2G 

IV. How Shall We Record Our Observations? 27 

V. How Can an Insect be Involved in Disease Transmission? . 27 

1. What Kind of Organisms Can Insects Carry? 27 

2. In What Manner May Insect Toxins Bring About Disease? . . 27 

3. Can Insects Themselves Cause Disease? 28 

4. Where May Insects Obtain the Organisms Which Cause Disease? 28 

5. How Can the Insect Transmit the Organism? 28 

6. What is the Course of the Organism in the Insect? ..... 29 

7. What is the Course of the Organism on Leaving the Insect? . . 29 
VI. What is Known About the Disease to be Investigated? . . 30 

VII. What Insects Should be Investigated? 30 

VIII. What is Necessary in the Transmission Experiments? ... 31 
IX. How Should Experimental Insects be Handled? 3-2 

III. A General Survey of the Needs of Entomological Sanitation in 
America 34 

The Insanitary Farm 35 

How to Improve Farm Sanitation 36 

The Insanitary Town 38 

How to Improve Sanitation 38 

Sanitary Problems of Cities 39 

Entomological Requirements of Municipal Sanitation 40 

Industrial Sanitation 41 

IV. A General Survey of the Seriousness of Insect Borne Diseases to 
Armies 43 

V. Relation of Insects to the Parasitic Worms of Vertebrates ... 50 

Mode of Infection of Insect Hosts 51 

Mode of Infection of Vertebrate Hosts 52 

Species of Worms Found in Ixsects 52 

Cestoda or Tapeworms 53 

Dipi/lidium caninum (Linnaeus, 1758) Railliet. 1892 53 

Hymenolepix diminuta (Rudolphi, 1819) Blanchard, 1891 5 t 

Hymcnolcpis nana (Siebold, 1852) Blanchard, 1891 V") 

Choanotoenia infundibulum (Bloch, 1779) Colin. 1899 56 

Other Tapeworms *>7 

Trematoda or Flukes 57 



CONTENTS 

PAGB 

Nematoda or Roundworms 58 

1. Parasitic Nematodes Whose Eggs or Larvae Leave the Body of the Final 
Host in the Feces * 60 

Protospirura muris (Gmelin, 1790) Seurat, 1915 60 

Spirocerca sanguinolenta (Rudolphi, 1819) Railliet & Henry, 1911 . 60 

Spirura gastrophila (Mueller, 1894) Marotel, 1912 . 61 

Gongylonema scutatum (Mueller, 1869) Railliet, 1892 62 

Gongylonema muscronatum Seurat, 1916 63 

Gongylonema brevispiculum Seurat, 1914 63 

Gongylonema neoplasticum (Fibiger and Ditlevsen, 1914) Ransom and 

Hall, 1916 63 

Ar duenna strongylina (Rudolphi, 1819) Railliet and Henry, 1911 . . 64 

Physocephalus sexalatus (Molin, 1860) Diesing, 1861 64 

Habronema muscoe (Carter, 1861) Diesing, 1861 65 

Habronema microstoma (Schneider, 1866) Ransom, 1911 67 

Habronema megastoma (Rudolphi, 1819) Seurat, 1914 67 

Acuaria spiralis (Molin, 1858) Railliet, Henry and Sisoff, 1912 . . 67 

Filaria gallinarum Theiler, 1919 68 

Ascar'is lumbricoides Linnaeus, 1758 68 

2. Parasitic Nematodes Whose First-Stage Larvae Occur in the Blood or 
Lymph of the Final Host and Leave the Body Through Ingestion by 
Blood-Sucking Insects 69 

Filaria bancrofti Cobbold, 1877 69 

Filaria (Loa) loa (Cobbold, 1864) 71 

Filaria demarquayi Manson, 1895 71 

Filaria philippinensis Ashburn and Craig, 1906 72 

Filaria tucumana Biglieri and Araoz, 1917 72 

Filaria cypseli Annett, Dutton and Elliott, 1901 72 

Filaria martis Gmelin, 1790 73 

Dirofilaria immitis (Leidy, 1856) Railliet and Henry, 1911 .... 73 

Dirofilaria repens, Railliet and Henry, 1911 74 

Acanthocheilonema perstans (Manson, 1891) Railliet, Henry and Lan- 

geron, 1912 . 74 

Acanthocheilonema grassii (Noe, 1907) Railliet, Henry and Langeron, 

1912 75 

Acanthocheilonema reconditum (Grassi, 1890) Railliet, Henry and Lan- 
geron, 1912 76 

Setaria labiato-papillosa (Alessandrini, 1838) Railliet and Henry, 1911 77 

Oncocerca 77 

3. Other Nematodes 77 

4. Mermithidae 78 

Gordiacea or Horse-Hair W t orms 78 

acanthocephala or thorn-headed worms 79 

Macracanthorhynchus hirudinaceus (Pallas, 1781) Travassos, 1916 ... 79 

Moniliformis moniliformis (Bremser, 1819) Travassos, 1915 79 

Compendium of Parasites Arranged According to Insect Hosts . . 79 

Aphaniptera (Siphonaptera)— fleas 79 

Diptera— flies 80 

Neuroptera 82 

Trichoptera — hairy-winged insects 83 

Lepidoptera — moths, butterflies 83 

Coleoptera — beetles 84 

Mallophaga — bird lice 86 

Isoptera — termites 87 

Odonata — dragonflies •. . 87 

Plectoptera — mayflies 87 

Plecoptera — stoneflies 88 

Orthoptera — cockroaches, etc 88 

Dermaptera — earwigs 88 

Myriapoda — millipedes, centipedes 88 

Acarina — ticks, mites 88 

Isopoda — sowbugs 89 

List of References - . . . . 89 



CONTENTS xi 

APTER PAGE 

VI. The Relations of Climate and Life and Their Bearings on the Study 

of Medical Entomology . 97 

VII. Diseases Borne by Non-Biting Flies 105 

Plant Organisms Carried by Non-Biting Flies 107 

Thallophy ta : Fungi: Schizomycetes : Coccaceae 107 

Thallophyta: Fungi: Schizomycetes: Bacteriaceae 109 

Thallophyta: Fungi: Schizomycetes: Spirillaeeae 115 

Summary of Plant Organisms 115 

Diseases of Unsettled Origin Probably Caused by Microorganisms 116 

Animal Organisms Carried by Non-Biting Flies 116 

Protozoa 116 

Sarcodina: Amcebina: Amcebidae 116 

Mastigophora: Protomonadina : Bodonidae -117 

Mastigophora : Polymastigina : Polymastigidae 117 

Mastigophora: Binucleata: Leptomonidae 117 

Mastigophora: Binucleata: Trypanosomidae 119 

Mastigophora: Spirochaetacea : Spirochaetidae 119 

Neosporidia: Myxosporidia: Nosemidse 120 

Protozoa: Neosporidia: Myxosporidia: Thelohanidse 120 

Higher Organisms Carried by Flies 120 

Platyhelmia: Cestoidea: Cyclophyllidea : Taeniidae 120 

Platyhelmia: Cestoidea: Cyclophyllidea: Hymenolepididae 120 

Platyhelmia: Trematcda: Malacotylea: Schistosomidae 120 

Nemathelminthes : Nematoda: Spiruridae 121 

Nemathelminthes : Nematoda : Ascaridae 121 

Nemathelminthes: Nematoda: Oxyuridse »». 121 

Nemathelminthes: Nematoda: Ancylostomidae 122 

Nemathelminthes: Nematoda: Trichosomidae 122 

Important General Text Books 123 

Special References 123 

VIII. Important Phases in the Life History of the Non-Biting Flies . . 126 

House Fly, Musca Domestic a Linnaeus 127 

The Blue Bottle Flies of the Genus Calliphora 130 

The Sheep Maggots or Green Bottle Flies 131 

Other Screw Worms and Blow Flies 132 

Other Excrement Breeders 135 

References 137 

IX. Common Flies and How to Tell Them Apart 138 

Table to Separate the Adult Flies 139 

The Larvae or Maggots 141 

Descriptions of Larvae or Maggots 141 

Table to Separate the Larvae (Maggots) 142 

Fannia canicularis Linnaeus and Fannia scalaris Fabricius 144 

Musca domestica Linnaeus 144 

Stomoxys calcitrans Linnaeus 145 

Muscina stabulans Fallen 146 

Calliphora erythrocephala Meigen 147 

Calliphora vomitoria Linnaeus . . 148 

Lucilia sericata Meigen 148 

Chrysomya macellaria Fabricius 149 

Sarcophagidce 150 

Bibliography 151 

X. The Control of the House Fly and Related Flies 153 

Repressive Measures 153 

Striking the Source . 153 

Manure 153 



xii CONTENTS 

CHAPTER PAGE 

Garbage 160 

Excreta 161 

Carcasses 161 

Miscellaneous Breeding Places 162 

Palliative Measures 162 

XI. Control of Flies in Barn Yards, Pig Pens and Chicken Yards . . . 167 

Repression op Flies in Barn Yard 167 

Fly Control in Pig Lots and Pens 170 

Prevention of Fly Breeding in Chicken Houses and Yards . . . 173 

XII. Myiasis — Types of Injury and Life History, and Habits of Species 

Concerned . 175 

Tissue-Destroying Forms 176 

subdermal mlgratory species 182 

Intestinal and Urogenital Myiasis 190 

Forms Producing Myiasis in Head Passages 193 

Bloodsucking Forms 195 

Some Bibliographical References 196 

XIII. Myiasis — Its Prevention and Treatment 200 

Tissue-Destroying Forms 200 

subdermal mlgratory species 204 

Species Causing Intestinal and Urogenital Myiasis ...... 205 

Species Infesting Head Passages 207 

Bloodsucking Species 208 

XIV. Diseases Transmitted by Bloodsucking Flies 209 

Plant Organisms Carried by Bloodsucking Flies 209 

Thallophyta: Fungi: Schizomycetes : Bacteriacese . . 209 

Thallophyta : Fungi: Schizomycetes: Coccacese 210 

Diseases of Unknown or Uncertain Origin 211 

Animal Organisms Transmitted by Bloodsucking Flies 212 

Protozoa 212 



Mastigophora : Binucleata 

Mastigophora : Binucleata 

Mas tigophora : Binucleata 

Mastigophora: Binucleata 



Hsemoproteidse 212 

Leucocytozoidse 214 

Trypanosomidse 214 

Leptomonidse 219 

Mastigophora: Spirochsetacea : Spirochsetidse 216 

Telosporidia: Hsemogregai inida : Hsemogregarinidse 219 

Metazoa . . 220 

Nemathelminthes : Nematoda: Filariidse 220 

Bibliography 220 

XV. Biological Notes on the Bloodsucking Flies 223 

Family Chironomid^e 223 

Midges 223 

Family Simuliid^e 224 

Buffalo Gnats 224 

Family Psychodid,® 226 

Pappataci Flies 226 

Family Culicidje 228 

Family Tabanid^e 228 

Horse Flies 228 

Family Muscid^e 228 

Bloodsucking Fly Larvae 228 

Biting Species of Musca 229 

True Biting Flies 229 

Stable Flies 230 



CONTENTS xiii 

CHAPTER PAGE 

Horn Flies 232 

Tsetse Flies 234 

Pupipara 235 

References 235 

XVI. Biology and Habits of Horse Flies 236 

Eggs and Egg Laying 237 

Larvae 240 

Pijp.E 243 

Life Cycle 243 

Habits of Adults 244 

Concerning Control Measures 245 

Bibliography 246 

XVII. Diseases Transmitted by Mosquitoes 247 

Diseases of Uncertain Origin Transmitted by Mosquitoes .... 248 

Plant Organisms Transmitted by Mosquitoes 249 

Thallophyta: Fungi , . 249 

Thallophyta: Fungi: Schizomycetes : Bacteriacese 249 

Animal Organisms Transmitted by Mosquitoes . 249 

Proiozoa 249 

Mastigophora : Binucleata: Hsemoproteidae . 249 

Mastigophora : Binucleata: Leucocytozoidae 250 

Mastigophora: Binucleata: Trypan osomidse 250 

Mastigophora: Binucleata: Leptomonidse 251 

Mastigophora: Binucleata: Plasmodidse 252 

Mastigophora: Spirochsetacea : Spiroehaetidse 259 

Metazoa 260 

Platyhelmia: Fasciolidse 260 

Nemathelminthes : Nematoda: Filariidse 261 

Nemathelminthes : Nematoda: Mermithidse 262 

References 263 

XVIII. What We Should Know About Mosquito Biology 266 

oviposition and the egg stage , 267 

The Larv.e and Their Habits 268 

The Pup.e 272 

Adult Mosquitoes 272 

Table of American Disease-Carrying Mosquitoes 273 

References 274 

XIX. Mosquito Control 275 

Prevention of Mosquito Breeding 275 

Scouting 275 

Determination of Source of Mosquitoes 276 

Leveling and Filling Water Holes 276 

Ditching and Clearing Streams and Swamps 276 

Clearing of Weed-Filled Bays and Lakes 277 

Drainage 277 

Larvicides 279 

Oiling 280 

Artificial Containers of Mosquito Larvae . . 282 

Fish as Mosquito Control 282 

Destruction of Adult Mosquitoes 283 

Protection from Mosquitoes 283 

Protection of Dwellings from Mosquitoes 288 

Protection of the Individual 283 

Bibliography . 285 



xiv CONTENTS 

CHAPTEH • PAGE 

XX. Louse Borne Diseases 286 

I. Direct Effect of Louse Attack 286 

1. Types of Pediculosis Corporis 286 

2. Types of Pediculosis Capitis 287 

3. Types of Phthiriasis 287 

4. Effects of Attack of Other Lice 288 

II. Transmission of Diseases by Lice 289 

1. Diseases of Plant Origin 289 

Thallophyta: Fungi: Ascomycetes : Gymnoascese 289 

Thallophyta : Fungi: Hyphomycetes . . . . . . . . . 289 

Thallophyta: Fungi: Schizomycetes : Coccaceae 289 

Thallophyta: Fungi: Schizomycetes: Bacteriacese .... 290 

Summary of Plant-Caused Diseases 290 

2. Diseases of Unknown or Uncertain Origin 291 

3. Diseases of Animal Origin 294 

Protozoa 294 

Mastigophora : Binucleata: Trypanosomidse 294 

Mastigophora : Binucleata: Leptomonidse 294 

Mastigophora: Spirochsetacea : Spirochsetidse 295 

Telosporidia : Haemogregarinida : Hsemogregarinidae ... 296 

Metazoa 297 

Platyhelmia: Cestoda: Cyclophyllidea: Taeniidae .... 297 

Bibliography 297 

XXI. The Life History of Human Lice 301 

References 311 

XXII. The Control of Human Lice ' 312 

The Ravages of Lice 312 

Reservoirs of Louse Breeding 313 

Control Measures 314 

Control of Lice on the Body 316 

Control of Crab Louse 316 

Control of Head Louse 316 

Control of Body Louse ' 317 

Control of Lice in Clothing 319 

1. Laundry 319 

2. Dry Cleaning 320 

3. Steam Sterilization 321 

4. Hot Air Delousing 324 

5. Fumigation 324 

6. Storage , . 326 

7. Impromptu Delousing Arrangements 326 

Control of Lice in Living Quarters 327 

Control of Lice in Hospitals 328 

Control of Lice in Hospitals 328 

Louse-Proof Garments for Medical Attendants, etc. . . _ 328 

Bibliography 328 

XXIII. Lice Which Affect Domestic Animals 330 

Part 1. Cattle Lice and Their Control 330 

Sucking Lice 331 

Biting Lice 332 

Methods of Study of Life History 333 

Control Measures 334 

Oils 334 

Sprays 335 

Miscellaneous Remedies 337 

Time for the Application of Control Measures 338 

Skin Injuiies 338 



CONTENTS xv 

CHAPTER PAGE 

Part 2. Lice Affecting Chickens, Hogs, Goats, Sheep, Horses, and 

Other Animals 339 

Lice Infesting Domestic Fowls 339 

Lice Infesting Rabbits, Cats and Dogs 343 

The Hog Louse 344 

Lice Attacking Sheep 34.5 

Biting and Sucking Lice of Goats 346 

Lice of the Horse 347 

Important Bibliographical References 348 

XXTV. Diseases Carried by Fleas 350 

Plant Organisms Transmitted by Fleas 350 

Thallophyta: Fungi: Schizomycetes: Bacteriaceae 350 

Animal Organisms Transmitted by Fleas 352 

Protozoa 352 

Mastigophora : Binucleata: Trypanosomidae 352 

Mastigophora: Binucleata: Leptomonidae 354 

Mastigophora: Spirochaetacea: Spirochaetidae 355 

Telosporidia : Gregarinida: Agrippinidae 355 

Telosporidia : Haemogregarinida : Haemogregarinidae 355 

Metazoa 355 

Platyhelmia: Cestoidea: Cyclophillidea: Taeniidae 355 

Platyhelmia: Cestoidea: Cyclophillidea: Hymenolepididae .... 356 

Nemathelminthes: Nematoda: Spiruridae . ... . 357 

Nemathelminthes : Nematoda: Filariidae 357 

Summary 357 

References 358 

XXV. The Life History and Control of Fleas 360 

Factors Influencing Abundance of Fleas 366 

Control of Fleas 367 

List of References 371 

Notes on the Chigoe, Dermatophilus Penetrans 373 

XXVI. Cockroaches 374 

Biology 375 

Key to the Four Principal Household Cockroaches 376 

Blatta orientates (Linnaeus) 376 

Blattella germanica (Linnaeus) , Caudell 377 

Periplaneta americana (Linnaeus) 378 

Periplaneta australasioe (Fabricius) Burtneister 380 

Remedies 380 

Fumigation 380 

Hydrocyanic Acid Gas 380 

Carbon Bisulphide 380 

Pyrethrum Powder . 381 

Sulphur 381 

Poisons 381 

Sodium Fluoride 381 

Borax 381 

Pyrethrum Powder 382 

Phosphorus 382 

Sulphur 382 

Castor Oil 382 

Traps :5S-2 

Enemies 382 

XXVII. Diseases Transmitted by the Cockroach 383 

Plant Organisms 383 

Thallophyta : Fungi : Coccacese 

Thallophyta: Fungi: Bacteriaceae 384 

Thallophyta: Fungi: Spirallaceae :?S7 



xvi CONTENTS 

CHAPTER PAGE 

Animal Organisms 388 

Protozoa 388 

Sarcodina: Amoebina: Amoebidse 388 

Mastigophora : Polymastigina : Tetramitidse 388 

Mastigophora : Binucleata: Leptomonidse 388 

Telosporidia : Gregarinida: Gregarinidse 388 

Telosporidia: Coccidiidea: Eimeriidse 388 

Neosporidia: Myxosporidia : Thelohaniidse 388 

Ciliata: Heterotricha: Bursarinidse 388 

Metazoa 389 

Platyhelmia: Cestoidea: Hymenolepididse 389 

Nemathelminthes : Acanthocephala: Gigantorhynchidse 389 

Nemathelrainthes : Nematoda: Spiruridse 389 

Nemathelminthes: Nematoda: Oxyuridse 389 

References 390 

XXVIII. The Bedbug and Other Bloodsucking Bugs: Diseases Transmitted, 

Biology and Control 391 

Diseases of the Plant Kingdom Transmitted by Bugs . . . . . 392 

Thallophyta: Fungi: Bacteriacese 392 

Diseases of Unknown Origin 393 

Diseases of the Animal Kingdom Transmitted by Bugs 393 

Protozoa 393 

Mastigophora: Binucleata: Trypanosomidse 393 

Mastigophora: Binucleata: Leptomonidse 395 

Mastigophora: Spirochsetacea : Spirochsetidse 398 

Life History Notes 399 

Treatment of Bites 401 

Control Measures 401 

List of References 401 

XXIX. Diseases Caused or Carried by Mites and Ticks 403 

Diseases Caused by Direct Attack of Ticks and Mites 403 

Diseases Carried by Mites and Ticks 411 

Diseases Caused by Plant Organisms 411 

Diseases of Unknown Origin 412 

Diseases of Animal Origin 414 

Protozoa 414 

Mastigophora: Binucleata: Trypanosomidse 414 

Mastigophora: Binucleata: Leptomonidse 414 

Mastigophora: Spirochsetacea: Spirochsetidse 418 

Telosporidia: Hsemogregarinida : Hsemogregarinidse 420 

Summary 424 

List of References 427 

XXX. The Biologies and Habits of Ticks 430 

Bibliographic References 438 

XXXI. Control of Ticks 440 

List of References 449 

XXXII. Flies and Lice in Egypt 450 

The Sultan's Funeral 452 

XXXIII. Insects in Relation to Packing Houses 453 

Insect-Breeding Places and Their Treatment 455 

Protection Against Insects 458 

A Bibliography of Literature Dealing with Sanitation of Meat 

Packing Establishments 459 



CONTENTS xvii 

CH AFTER PAGE 

XXXIV. Insect Poisoning and Miscellaneous Notes on the Transmission' of 

Diseases by Insects 461 

Scorpion Poisoning 461 

Spider Poisoning 463 

Centipede Poisoning 464 

Centipedes in Nasal Cavities and Alimentary Canal 466 

Lepidopterous Larvae Poisoning . 466 

Bee, Wasp and Ant Stings . 467 

Honey Poisoning : 468 

Anaphylaxis 468 

Poisoning from Eating Insects 469 

Kissing Bugs 469 

Dermatitis Caused by Beetles 469 

Beetles as Carriers of Disease Germs 469 

List of References 470 

Summary 472 

XXXV. A Tabulation of Diseases and Insect Transmission 473 

Index 499 



■■ 



CONTENTS BY AUTHORS 

By W. Dwight Pierce — Bureau of Entomology 



PAGE 

How Insects Can Carry or Cause Disease 19 

Some Necessary Steps in any Attempt to Prove Insect Transmission or Causation of 

Disease 25 

A General Survey of the Needs of Entomological Sanitation in America . . 34 
A General Survey of the Seriousness of Insect Borne Diseases to Armies . 43 
Relations of Climate and Life, and their Bearings on the Study of Medical Ento- 
mology , 97 

Diseases Borne by Non-Biting Flies 105 

Important Phases in the Life History of the Non-Biting Flies 126 

The Control of the House Fly and Related Flies 153 

Diseases Transmitted by Bloodsucking Flies 209 

Biological Notes on the Bloodsucking Flies 223 

Diseases Transmitted by Mosquitoes 247 

Mosquito Control 275 

Louse Borne Diseases 286 

Diseases Carried by Fleas 350 

Diseases Transmitted by the Cockroach 383 

The Bedbug and Other Bloodsucking Bugs: Diseases Transmitted, Biology and 

Control 391 

Diseases Caused or Carried by Mites and Ticks 403 

Insect Poisoning and Miscellaneous Notes on the Transmission of Diseases by 

Insects 461 

A Tabulation of Diseases and Insect Transmission . 473 

By W. Dwight Pierce and C. T. Greene, Bureau of Entomology 

What We Should Know About Mosquito Biology 266 

By W. Dwight Pierce and Robert H. Hutchison, M.A., Bureau of Entomology 

The Life History of Human Lice 301 

The Control of Human Lice 312 

By B. H. Ransom, Ph.D., Zoologist, Bureau of Animal Industry 

Relation of Insects to the Parasitic Worms of Vertebrates 50 

By F. C. Bishopp, B.S., Bureau of Entomology, In Charge Animal Insect Investigations 

Control of Flies in Barn Yards, Pig Pens and Chicken Yards 167 

Myiasis. Types of Injury and Life History and Habits of Species Concerned . 175 

xix 



xx CONTENTS BY AUTHORS 

PAGE 

Myiasis. Its Prevention and Treatment 200 

The Life History and Control of Fleas . . 360 

The Biologies and Habits of Ticks 430 

The Control of Ticks 440 

By J. L. Webb, M.S., Bureau of Entomology 
Biology and Habits of Horse Flies 236 

By G. H. Lamson, Jr., M.S., Entomologist Storrs (Conn.) Agricultural Experiment 

Station 
Lice Which Affect Domestic Animals . 330 

By A. N. Caudell, B.S., Bureau of Entomology; Curator of Orthoptera, U. S. National 

Museum 
Cockroaches 374 

By H. A. Ballou, Ph.D., Imperial Entomologist, Barbados 
Flies and Lice in Egypt 450 

By E. W. Laake, B.S., Bureau of Entomology 
Insects in Relation to Packing Houses 453 



LIST OF TEXT FIGURES 

FIGCBE PAGE 

1. Cross Section of Mann's Hillside Incinerator, Used at U. S. Marine Camp, 

Qttantico, Va. (Manx) 46 

2. Modification of Mann's Hillside Incinerator, Adapting It to Level Ground. 

(Mann) 46 

3. Small Incinerator of the Ferguson Type, for Use of Small Units, and Ca- 

pable of Transportation. (Mann) 46 

4. Straddle Trench Latrines, 1 foot wide, 2 feet deep, 3 feet long, for Field 

Operations at Temporary Locations. (Mann) 47 

5. Covered Pit Latrine Level with Ground, a Semi-Permanent Type. (Mann) 47 

6. Garbage Can with Top Converted into Portable Urinal for Use in Com- 

pany Street at Night. (Mann) 47 

7. Urine Soakage Pit, in Cross Section. (Mann's Modification from Lelean) 48 

8. Chart Showing the Zones of Life Reaction to Temperature and Relative 

Humidity. (Pierce) 98 

9. Suggested Curves of the Responses of Average Americans to Humid Tem- 

peratures. (Pierce) 10-2 

10. Mouth Parts of Flies: a, suctorial type; 6, biting type. (Greene) 13S 

11. Diagrammatic Sketch of the House Fly, Musca domestica. (Greene) .... 139 

1-2. Abdominal Markings of Three Common House Flies: a, The house fly, 
Musca domestica; b, little house fly, Fannia canicularis; c,- stable fly, Stomoxys cal- 
citrans (Greene). In these diagrams the relative size of the abdomen is shown. 
The light areas in a and b represent yellow markings and are variable in size. In 
fig. c the markings of the last segment may be present or absent 140 

13. Characters of a Muscid Fly Larva. (Greene.) Segment 1 is the head; 

2-4 are thoracic segments; 5-11 are abdominal. Segment 11 really contains the 
seventh to tenth abdominal segments, the spiracles being on the eighth, the anus 
is the tenth 14-2 

14. Larva of the Little House Fly, Fannia canicularis. Greatly enlarged. (Howard 

and Pierce, Drawing by Bradford) 143 

15. Dorsal View of Eighth Abdominal Segment of the Larva of Fannia 

canicularis. Very highly magnified. (Drawing by Bradford) 143 

16. Ventral View of Terminal Segments of Fannia canicularis; the ninth and 

tenth segments are comprised in the small zone around the anus. Very highly 
magnified. (Drawing by Bradford) 143 

17. Larva of Fannia scalaris, the Latrine Fly. Greatly magnified. (Howard and 

Pierce, Drawing by Bradford) 144 

18. Dorsal View of Eighth Abdominal Segment of Fannia scalaris. Very highly 

magnified. (Drawing by Bradford) 144 

19. Ventral View of Terminal Segments of Fannia scalaris: the ninth and tenth 

segments are comprised in the small zone around the anus. Very highly magnified. 
(Drawing by Bradford) 144 

20. Larva of Musca domestica: Dorsal View of Head and Prothorax. (Greene) 145 

21. Larva of Musca domestica: Lateral View of Terminal Segments. (Greene) 

The spiracles are located on the eighth abdominal segment. The ninth and tenth 
segments are ventral and not very distinct, enclosing the anus 145 

22. Larva of Musca domestica: Enlarged Sketch of Right Stigma) Plate. These 

plates are less than their breadth apart. (Greene) 145 

23. Larva of Stomoxys calcitrans: Enlarged Sketch of Thoracic Spiracles. (Greene) . 14G 

xxi 



xxii LIST OF TEXT FIGURES 

FIGUBE PAGE 

24. Larva of Stomoxys calcitrans: Enlarged Sketch of Right Stigmal Plate. These 

plates are one and one-half times their breadth apart. (Greene) 146 

25. Larva of Muscina stabulans: a, Side view of head and prothorax; b, anterior or 

thoracic spiracles; c, side view of terminal segments of abdomen. (Greene) • . . 147 

26. Larva of Muscina stabulans: Enlarged Sketch of Right Stigmal Plate. These 

plates are less than their breadth apart. (Greene) 147 

27. Larva of Calliphora erythrocephala: Side View of Head and Prothorax. (Greene) 148 

28. Larva of Calliphora erythrocephala: Enlarged Sketch of Left Stigmal Plate. These 

plates are one and one-quarter times their breadth apart. (Greene) 148 

29. Larva of Chrysomya macellaria: Enlarged Sketch of Side of Head and Prothorax. 

(Greene) 149 

30. Larva of Chrysomya macellaria: Enlarged Sketch of Left Stigmal Plate. These 

plates are less than their breadth apart. (Greene) 149 

31. Larva of Lucilia sericata: a, dorsal view of head and prothorax; b, lateral view of 

head and thorax; c, lateral view of last abdominal segments. (Greene) .... 149 

32. A Maggot Trap for Housefly Control. View of the maggot trap, showing the 

concrete basin containing water in which larvae are drowned, and the wooden plat- 
form on which manure is heaped. (Hutchison) 155 

33. Use of Flytrap in Connection with Manure Bin: a, Block of wood set in 

ground to which lever raising door is hinged 157 

34. Top of Garbage Can with Small Balloon Flytrap Attached 160 

35. Conical Hoop Flytrap; Side View: a, Hoops forming frame at bottom; b, hoops 

forming frame at top; c, top of trap made of barrel head; d, strips around door; 
e, door frame;/, screen on door; g, buttons holding door; h, screen on outside of 
trap; i, strips on side of trap between hoops; j, tips of these strips projecting to 
form legs; k, cone; I, united edges of screen forming cone; m, aperture at apex of 
cone. (Bishopp) 163 

36. Plans of Open Hog-Feeding Trough. (Bishopp) 171 

37. Full Grown Larva of the Human Bot, Dermatobia hominis. (Drawing by Brad- 

ford.) Actual length 14.5 mm 187 

38. Full Grown Larva of the Tumbu-Fly, Cordylobia anthropophaga. (Grunberg.) 

Ventral view, x 6. (From Austen) 189 

39. The Tumbu-Fly, Cordylobia anthropophaga. (Grunberg) Female, x 6. (From 

Austen) 189 

40. Nose Protection for Horse Against Attacks of the Nose Fly, Gastrophilus 

hcemorrhoidalis. (Dove) 205 

41. Chart Illustrating the Life Cycle of Hcemoproteus columbce, the Cause of 

Pigeon Malaria. (Pierce) 213 

42. Chart Illustrating the Life Cycle of Trypanosoma gambiense, the Cause of 

Gambian Sleeping Sickness. (Pierce) 215 

43. Larva of a Buffalo Gnat, Simulium. (Jobbins-Pomeroy) 225 

44. Eggs of the Stable Fly, Stomoxys calcitrans Attached to a Straw. Greatly 

enlarged. (After Bishopp) 230 

45. The Stable Fly: Larva or Maggot. Greatly enlarged. (After Bishopp) . . 230 

46. The Stable Fly: Adult Female, Side View, Engorged with Blood. Greatly 

enlarged. (After Bishopp) 230 

47. Life Cycle of Plasmodium, Cause of Pernicious Malaria. (Pierce) . . . 252 

48. Eggs and Larvae of Culex. Enlarged. (Howard) 268 

49. Eggs of Malaria Mosquitoes: a, Anopheles punctipennis ; b, A. quadrimaculatus ; 

c, A. crucians. (After Howard, Dyar and Knab) 268 

50. Larva of the Yellow-Fever Mosquito. Much enlarged. (Howard) .... 269 

51. Larva of the Malaria Mosquito, Anopheles punctipennis. (After Howard, 

Dyar, and Knab) 271 

52. Pupa of Culex. Greatly enlarged. (Howard) 272 

53. Pupa of Anopheles quadrimaculatus. Greatly enlarged. (Howard) 272 



LIST OF TEXT FIGURES xxiii 

FIGURE PAGE 

54. Pupa of Aedes argenteus, the Yellow Fever Mosquito. Greatly enlarged. 

(After Howard, Dyar, and Knab) 272 

55. Types of Mosquito Mouth Parts: a, Short palpus form; b, long palpus form 

(Greene) 273 

56. Adult Culex sollicitans. Much enlarged. (Howard) 273 

57. The Yellow Fever Mosquito Aedes argenteus: Adult Female. Much enlarged. 

(Howard) 273 

58. A Malarial Mosquito, Anopheles quadrimaculatus: Male at Left and Female 

at Right. Greatly enlarged. (Howard) 274 • 

59. Submersible Automatic Bubbler for Distributing Oil Over Surface of 

Water. (Ebert) 281 

60. Method of Petrolization with Oil-Soaked Sawdust. (Ebert) 281 

61. Wristlet Method Used for Breeding Lice. (Hutchison, Photo by Dovener) 303 

62. Chart Illustrating the Life Cycle of Trypanosoma lewisi. (Pierce) .... 353 

63. Chart Illustrating the Life Cycle of the Dog Tape Worm, Dipylidium cani- 

num. (Pierce) . 356 

64. Larva of the European Rat Flea, Ceratophyllus fasciatus. Greatly enlarged. 

(Bishopp) 361 

65. The Dog Flea, Ctenocephalus canis: a, Egg; b, larva in cocoon; c, pupa; d, adult; 

e, mouth parts of same from side;/, antenna; g, labium from below, b, c, d, much 
enlarged; a, e, /, g, more enlarged. (From Howard) 362 

66. The Human Flea, Pulex irritans: Adult Female. Greatly enlarged: (Bishopp) 362 

67. The Human Flea, Pulex irritans: Adult Male. Greatly enlarged. (Bishopp) 363 

68. The European Rat Flea, Ceratophyllus fasciatus: Adult Female. Greatly 

enlarged. (Bishopp) 364 

69. The Sticktight Flea, Echidnophaga gallinacea: Adult Female. Greatly en- 

larged. (Bishopp) 365 

70. Head of Rooster Infested with the Sticktight Flea, Echidnophaga gallinacea. 

Somewhat reduced. (Bishopp) 366 

71. The Oriental Roach, Blatta orientalis: a, Female; b, male; c, side view of female; 

d, half-grown specimen. All natural size. (Marlatt) " 377 

72. The German Roach, Blattella germanica: a, First stage; b, second stage; c, third 

stage; d, fourth stage; e, adult;/, adult female with egg case; g, egg case, enlarged; 

h, adult with wings spread. All natural size except g. (From Riley) 378 

73. The American Roach, Periplaneta americana: a, View from above; b, from be- 

neath. Enlarged one-third. (Marlatt) . 379 

74. Bedbug: Egg and Newly Hatched Larva: a, Larva from below; b, larva 

from above; c, claw; d, egg; e, hair or spine of larva. Greatly enlarged, natural size 

of larva and egg indicated by hair lines. (Marlatt) 396 

75. Bedbug: a, Larval skin shed at first molt; b, second larval stage immediately after 

emerging from a; c, same after first meal, distended with blood. Greatly enlarged. 
(Marlatt) 396 

76. Bedbug: Adult Before Engorgement. Much enlarged. (Marlatt) .... 397 

77. Bedbug, Cimex lectularius: a, Adult female, engorged with blood; b, same from below; 

c, rudimentary wing pad; d, mouth parts, a, b, much enlarged; c, d, highly magni- 
fied. (Marlatt) 397 

78. Chart of Life Cycle of Babesia canis, the Cause of Canine Malignant Jaun- 

dice. (Pierce) 416 

79. Life Cycle of Hcemogregarina canis, the Cause of Canine Anemia. (Pierce) . 4-21 

80. Tick Life Cycle, Type I. (After Nuttall) 423 

81. Tick Life Cycle, Type II. (After Nuttall) 423 

82. Tick Life Cycle, Type III. (After Nuttall) 425 

83. Tick Life Cycle, Type IV. (After Nuttall) 425 

84. Tick Life Cycle, Type V. (After Nuttall) 426 

85. Tick Life Cycle, Type VI. (Pierce) 426 

86. The Rocky Mountain Spotted Fever Tick, Dermacenior andersoni. (Bishopp) . 437 

87.' Model Chicken Roost. (Bishopp) . 446 

88. A Centipede, Scolopendra morsitans. (Bradford) Hi,") 



LIST OF PLATES 

The House or Typhoid Fly, Musca domestica. Greatly enlarged. 

(Howard and Pierce, Photo by Dovener) Frontispiece 

PLATE PAGE 

I. Screw Worms and Blow Flies. (Howard and Pierce, Photos by Dove- 
ner) 133 

Fig. 1. The blue bottle fly, Calliphora vomitoria. 
" 2. The green bottle fly, Lucilia ecesar. 
" 3. The American screw worm, Chrysomya macellaria. 
" 4. The black blow fly, Phormia regina. 

II. Eggs of the American Screw Worm, Chrysomya macellaria, On Meat. 

(Bishopp) 134 

III. Flies with Dangerous Habits. (Howard and Pierce, Photos by Dove- 

ner) 136 

Fig. 1. A flesh fly, Sarcophaga sarracenice. 
" 2. The non-biting stable fly, Muscina stabulans. 
" 3. The lesser house fly, Fannia canicularis. 
" 4. The brilliant green fly, Pseudopyrellia cornicina. 

IV. Screw Worm Injury to a Yearling Calf. (Bishopp) 150 

V. Manure Box with Flytrap Attached. (Bishopp) 155 

VI. Manure Spreader. (Bishopp) 157 

VII. Road Drag in Use Scraping Manure in a Cow Lot on a Tennessee Farm. 

(Bishopp) 159 

VIII. Undesirable Conditions Which Are Overcome by Use of the Maggot 
Trap. A manure pile covering a large area and having little depth. Illus- 
trating the conditions which favor the greatest loss of nitrogen, and at the 
same time offer the best breeding ground for flies. (Hutchison) . . . 159 

IX. Carcass Partly Destroyed by Larvae of the American Screw Worm 

Fly, Chrysomya macellaria. (Bishopp) 177 

X. Horse Bot Flies. (Dove) . 183 

Fig. 1. Gastrophilus intestinalis, the common bot. 
" 2. Gastrophilus hoBmorrhoidalis, the nose fly. 

XL Phases of the Life Cycle of Bot Flies. (Bishopp) 184 

Fig. 1. Empty eggs of the cattle bot, Hypoderma lineata. 
" 2. Eggs of the common horse bot, Gastrophilus intestinalis. 
" 3. Full grown larva of Hypoderma lineata. 
" 4. Empty puparium of Hypoderma lineata. 
" 5. Empty puparium of Gastrophilus intestinalis. 

XII. Method of Attack by the Common Horse Bot, Gastrophilus intestinalis. 

(Bishopp) 185 

Fig. 1. Eggs on horse's legs. 
" 2. Larvae attached to walls of stomach, showing lesions caused by 
removed bots in center. 

XIII. Method of Attack by the Cattle Bot, or Heel Fly, Hypoderma 

lineata. (Bishopp) 186 

Fig. 1. Fly ovipositing on cow's leg. 
" 2. Portion of cow's back showing larvae, empty holes, and pus exudate. 
" 3. Heavily infested cow. 

XIV. Trench Prepared for Burning Carcass. (Bishopp) 201 

XXV 



xxvi LIST OF PLATES 

PLATE PAGE 

XV. Pup.e of Simulium. (After Jobbins-Pomeroy) 227 

Fig. 1. Respiratory filaments of pupa of Simulium vittatum. 
" 2. Pupa of Simulium venustum, in pupal case. 
' 3. Pupa of Simulium bracteatum: A, Side view of filaments. 
" 4. Pupa of Simulium jenning si. 
" 5. Pupa of Simulium pictipes, in pupal case. All greatly enlarged. 

XVI. The Stable Fly, Stomoxys calcitrans. (Bishopp) 231 

Fig. 1. Eggs in straw. 
" 2. Pupae in straw. 
" 3. Adults on leg of cow. 

XVII. Straw Stack Showing Proper Method of Building Straw Stack. (Bis- 

hopp) 232 

XVIII. The Horn Fly, Lyperosia irritans. (Bishopp) 233 

Fig. 1. Flies on cow. 
" 2. Cow pasture showing droppings improperly left to breed flies. 

XIX. Tabanidje Attacking Cattle: Tabanus pkcenops on cow's jaw, and T. 

punctifer on top of shoulder. (Bishopp) . 236 

XX. Tabanus punctifer. (Webb, Photos by Dovener) 238 

Fig. 1. Egg masses on grass. 
" 2. Larva, dorsal view. 
" 3. Larva, lateral view. 
" 4. Pupa, lateral view. 
" 5. Pupa, ventral view, 

XXL The Clothing Louse, Pediculus corporis. (Pierce and Hutchison, 

Photos by Dovener) 302 

Fig. 1. Female, ventral view. 
" 2. Male, dorsal view. 

XXII. Eggs of the Clothing Louse, Pediculus corporis 305 

Fig. 1. Mass of eggs, slightly reduced, between seams of trousers (Photo 
by Dovener.) 
" 2. Great enlargement showing eggs hatching. (Photo by Paine.) 
" 3. Very great enlargement showing structure of eggs with exuviae within. 
(Photo by Paine.) 

XXIII. Steam Sterilizer in Delousing Station of U. S. Army Medical 
Corps. The carriage is transferred along the rails in the foreground to rails 
leading into the other room where another carriage is seen. (Hutchison) 323 

XXIV. Scaly Leg Mite on Chickens. (Bishopp) .... 406 

Fig. 1. Scaly feet of chickens, caused by mite attack. 
" 2. Scaly leg mites, greatly enlarged. 

XXV. Dipping Scaly Legs of Chicken in Crude Oil. (Bishopp) 407 

XXVI. The Fowl Tick, Argas persicus. (Bishopp) 433 

Fig. 1. Larvse under feathers of chicken. 
" 2. Unengorged male, ventral view; much enlarged. 
' 3. Female with eggs, dorsal view; greater enlargement. 
" 4. Unengorged female, ventral view; same enlargement as fig. 2. 

XXVII. The Cattle Tick, Boophilus annulatus. (Bishopp) 435 

Fig. 1. Fully engorged female. 
" 2. Engorged female depositing eggs. 

XXVIII. Spraying Chicken House with Oil by Means of Knapsack Spray Pump. 

(Bishopp) . 447 



SANITARY ENTOMOLOGY 



CHAPTER I 

How Insects Can Carry or Cause Disease * 
W. Dwight Pierce 

Our nation, as well as all our world civilization, is facing the greatest 
crisis in its existence in these days of reconstruction. We must con- 
serve human energy and keep it at its greatest possible point of effi- 
ciency. This means above all that questions of health are foremost 
today. 

Entomology bears a twofold relationship to health. Adequate food 
supply upon which human and animal health are contingent is dependent 
to a greater or less degree upon insect depredations. This is the side of 
entomology which has in the past received most of the recognition, that 
is, agricultural entomology. It has been generally recognized that insects 
also bear a direct relationship to health, but the public has more or less 
discounted the relationship, with the result that our public appropria- 
tions for the study of insects affecting crops are approximately thirty 
times as great as the appropriations for the study of insects affecting 
the health of man and animals. The present course of lectures aims to 
give the latest views in this almost unworked field of medical entomology, 
with a view toward demonstrating the necessity of obtaining a better 
balance in the two great phases of economic entomology. 

The scope of the course embraces studies of the relationship of 
insects to disease, the life history of the insects which cause disease, 
and the best methods of prevention of disease causation by insects. It 
is intended to be placed in the hands of the men who will conduct work 
along these lines, to show them why insects are dangerous, how they are 
dangerous, what their habits disclose as weak points subject to attack, 
and finally, how to go about controlling them. 

In my opinion the near future will see a group of professional sanitary 
entomologists whose services will be available to solve the insect prob- 

1 This lecture was given on May 20, 1918, and mimeographed copies were dis- 
tributed May 22. It has been considerably revised for the present course. 

19 



20 SANITARY ENTOMOLOGY 

lems of municipalities, communities, and armies, as well as household and 
commercial problems. Municipal entomology has already been recognized 
in a small way by certain cities. It will become better known only by 
the work of entomologists themselves who are men of vision. The prob- 
lems involved in entomology sanitation demand an intensive and spe- 
cialized training which few of us received in school. If we would fit 
ourselves for such work it will demand great effort on our part. 

CLASSIFICATION OF METHODS BY WHICH INSECTS CAN CARRY OR 

CAUSE DISEASE 

Long before any one knew of causative organisms in medicine it was 
recognized that insects might be productive of disease. We may there- 
fore assume as our first category the diseases actually caused by the 
insects themselves. 

(I.) Diseases caused directly by insects. — We must recognize, for 
the sake of arrangement, all pathological conditions brought about by 
insects whether of a serious nature or not. 

1. Entomo phobia. — The fear of insects, both harmless and harmful, 
is a common ailment, amounting in many people to an obsession. I know 
of a young lady who became so frantic over the presence of a huge dragon 
fly in the automobile that the attempt to catch it led to a serious 
accident. Recently a serious automobile accident was caused by a bee 
sting. Many women become frantic at sight of large insects, and I 
have even seen men lose all sense of courage in the presence of an 
unknown species of insect. Obviously only patient and tactful educa- 
tion can ever cure such an obsession. 

2. Annoyance and worry. — We have all probably experienced a 
sense of annoyance, amounting sometimes to worry, from insects. It 
frequently happens that the annoyance increases to the point of causing 
acute nervous troubles which, it is quite conceivable, might lead to 
insanity with certain people. Animals are frequently driven frantic by 
insects such as buffalo gnats, mosquitoes, and horse flies, and lose all 
control of themselves. We may classify these different cases of insect 
annoyance in accordance with the sense which perceives it and commu- 
nicates its sensations to the brain. In this manner we have annoyance 
originating through sight, memory and imagination, sound, smell, taste, 
and feeling. 

Sight worry is initiated by the occurrence of unwanted insects in 
home or garden, or on one's person, or by their constant swarming 
about until patience is exhausted and one loses control of the nerves. 
A recently recorded case tells of a lady whose house was badly infested 
with book lice and who was fast becoming a nervous wreck when 



HOW INSECTS CAN CARRY OR CAUSE DISEASE 21 

entomological service was sought and the house freed of its pests. The 
constant moving of streams of ants across a floor, the sight of bedbugs 
or fleas, and many other common insect occurrences may cause a nervous 
person great perturbation. Recently a young entomologist was nau- 
seated and made very sick for hours by the sight of a louse infested 
man. 

Memory and imagination worry may be exemplified by the person 
impressed by anti-house fly propaganda, whose imagination sees on every 
fly multitudes of fatal disease germs. A person once injured by an 
insect will often experience acute revulsions of feeling on sight of another 
similar insect. 

Sound worry such as that induced by the singing of mosquitoes or 
the buzzing of horse flies will often lead to insomnia and in the cases of 
animals will cause great uneasiness. 

Smell worry or annoyance from insects often takes the form of great 
embarrassment. A few years ago in Dallas, Texas, Calosoma beetles were 
so numerous that people walking on the streets frequently would have 
one alight on them, and, in brushing the beetle off, would cause it to 
expel a sufficient quantity of liquid to make the person's presence 
undesirable in polite society. Many people are so sensitive to bedbug 
odors that when they sleep in infested rooms they are constantly aware 
of the odor and are possessed of a fear that they will be attacked by 
the bugs. 

Taste annoy amce is often caused by eating berries containing bugs, 
or which bugs or cockroaches have contaminated. This may often cause 
nausea. 

Finally, there is the worry aroused by contact of insects, the tingling 
sensation from insects crawling on the body, the peppery sting of gnats 
and mosquitoes, the itching sensations from vermin. Insomnia is a 
frequent result of such attacks. 

Thus as results of insect annoyance, we may have worry, nervous 
exhaustion, excitability, hallucinations, frenzy, insanity, nausea, insomnia 
and nervous chills. 

3. Accidental injury to sense organs. — There are numerous cases on 
record of insects accidentally obtaining access to the ear or nose and 
causing a stoppage of these organs, or of insects flying into the eyes 
causing severe irritation or even blindness. Certain species of gnats 
are especially annoying when there is any kind of catarrhal affection 
of these organs. Myriapods have frequently been recorded as entering 
the nose of a sleeping person. 

4. Poisoning. — Insects and the related arthropods may poison in a 
variety of ways. The bite of a tick, flea, spider, mosquito, horse fly, 
etc., may cause a severe local irritation and poisoning. The poisonous 



22 SANITARY ENTOMOLOGY 

centipedes have a poison sac opening on the front pair of legs. The 
scorpion stings with the tip of its tail. The bee, wasp, and ant sting 
with the ovipositor. Many of these injuries are very painful. Certain 
lepidopterous larvae are provided with barbed hairs which contain 
poisonous secretions, as the brown tail moth larva, and the larvae of 
Lagoa, Hyperchiria io, etc. Some insects emit poisonous secretions 
which blister (Meloid beetles). Some of the South American honey bees 
(Trigona) store poisonous honey. 

5. Paralysis. — The bite of several species of ticks (Dermacentor 
andersoni (venustus), for example, may cause paralysis with sometimes 
fatal results. Some spiders, ants, bees, wasps, and caterpillars inflict 
such a poisonous wound that temporary paralysis of the limb follows. 

6. Dermatosis. — Direct attack upon the body of men and animals, 
and parasitism thereon, is not unusual. We have as striking examples 
the dermatoses caused by lice (pediculosis), by the chigoe, the red 
bug (chiggers), the Dermatobia hominis, creeping worms, scab and 
itch mites (acariasis). Many of these attacks have serious after results, 
as for instance an acute attack by the chigoe may result in ainhum, the 
loss of a toe or a foot. Many secondary diseases obtain access to the 
body through the skin attack of insects. 

7. Myiasis and similar internal attacks. — Under this heading are to 
be considered cases in which insects are present in the tissues of internal 
organs of the body. The occurrence of insects has been recorded in 
organs of the head, in the intestinal canal, the reproductive organs, 
and the body wall. When the insect is a fly the disease is called Myiasis. 
When a beetle is the cause, the disease is called Canthariasis, and if a 
lepidopterous larva is responsible it is known as Scholeciasis. Many 
species of flies have been recorded as occurring in the human body. These 
will be studied in detail in a later lesson. 

(II.) Diseases carried by insects. — The ways in which insects may 
carry diseases are very diverse, due to the great differences not only in 
the habits of the insects, but also of the disease organisms and the 
hosts. 

1. Diseases carried by insects to food. — When insects carry disease 
germs to food or water we speak of the transmission as contaminative. 
Contaminative transmission of disease organisms to food by insects is 
naturally the simplest manner of transmission. This is necessarily done 
by insects which frequent excretionary substances and also visit foods, 
such as certain flies, ants, roaches, and beetles. It is obvious that we 
must look upon all insects which breed in fecal matter, sputum, etc., as 
potential disease carriers. Considerable research has already been con- 
ducted to prove the actual role of many species of coprophagous insects. 
The role of the carrier may either be mechanical or biological. 



HOW INSECTS CAN CARRY OR CAUSE DISEASE 23 

Many disease organisms are transmitted by insects which exercise 
apparently only a mechanical role. Principal among these are bacteria 
and certain parasitic worms. Many of the bacteria may be taken up by 
fly and beetle larvae, and by adult flies, beetles, roaches, and ants, and be 
carried on the body or ingested and passed through the body and out 
in the feces without modification or multiplication. A number of species 
of parasitic worms may be taken up in the egg stage by insects and 
deposited in the insect's feces. If such infested feces happen to be 
deposited on food, contamination and infection may conceivably follow. 

Certain other organisms which are carried by insects to food pass 
part of their life history in the insects. Such are some of the nematodes 
that may be ingested by coprophagous insects, which in turn are eaten 
by the animals that serve as final hosts of the parasites. 

2. Diseases carried by insects to wounds. — We can make the same 
division of these diseases into mechanical and biological carriage. The 
transmission of anthrax, leprosy, ophthalmia, and such diseases, from 
sore to sore or from excreta to sore is purely mechanical. When the 
organism passes part of its life cycle in the insect we might call the 
transmission biological. As examples of such types of transmission we 
may cite European relapsing fever and trench fever, louse-borne diseases 
which gain access to the body by the scratching in of fragments of the 
lice or their excreta. 

3. Diseases gaining access through direct attack of insect. — Most of 
the protozoal diseases and some of the parasitic worms gain access to 
the body of the vertebrate host by direct inoculation, or indirectly, at 
the time of feeding. When the organism is taken up by the insect 
it begins its development in the insect body and finally reappears in the 
salivary glands or some other position adjoining the mouth parts, the 
inoculation occurring during the blood feast. Such is the inoculation of 
malaria, yellow fever, and Rocky Mountain spotted fever. But other 
disease organisms pass through the intestinal canal of the insect and out 
in the feces and yet obtain access to the wound by being washed into it by 
body secretions of the insect, as is the case of the organism of African 
relapsing fever inoculated by the tick Ornithodoros moubata. 

WHY IT IS NECESSARY TO KNOW HOW INSECTS CARRY DISEASE 

In the foregoing discussion I 'have attempted to analyze the methods 
by which insects can cause or carry disease. There is also a practical 
side of the question. We must know the why and the wherefore and the 
what to do. 

Without a conception of the role of the insect we cannot give suf- 
ficient force to our arguments, or reasons for taking a particular course 



24 SANITARY ENTOMOLOGY 

of action. For instance, if we were mereW to go before the inhabitants 
of a Montana valley suffering from Rocky Mountain spotted fever and 
say : "We are going to put down this epidemic, you must dip your horses 
and trap all the rabbits and rodents on your place," what kind of an 
answer would we get? If the Public Health Service had stepped into 
New Orleans on the announcement of a plague case and ordered every- 
body to rat-proof their cellars, without further reason, they would have 
been driven away. 

If a sanitary officer reports to his superior that a certain thing 
must be done, requiring a considerable outlay of money and the use of 
a good many men, he must be able to give him a strong, forceful argu- 
ment to prove that he is right. Army officers, and in fact most exec . 
officers, want brief answers. The subordinate must therefore have his 
information on the tip of his tongue. 

We have seen by the above discussion that the bites of insects must 
be avoided. Where disease-carrying insects are present, the greater 
the concentration of human beings or animals, the greater the necessity of 
exercising control, whether it be in a municipality, a commercial estab 
lishment, an army, a stock yards, or a ranch. It is incumbent upon all 
men charged with entomological sanitation to learn the bloodsucking 
fauna about them. Without a knowledge of how mosquitoes, horse flies, 
bedbugs, lice, stable flies, gnats, and ticks breed, one can scarcely proceed 
to prevent their breeding and consequently cannot protect men and 
animals from their attacks. 

One must always prevent insects from coming in contact with wounds. 
This is especially important in hospitals and during times of epidemics. 
It is at all times imperative to keep food untouched by anything in the 
form of insect life. Insects must not be tolerated in dwellings, no 
matter whether there is evidence against them or not. There is evidence 
against most of them. 

Domestic animals must likewise be kept as free as possible from 
insects. Some day we will recognize that stables should be as well 
proofed against flies as dwellings are now. There are more inducements 
for flies and other noxious insects around a stable than anywhere else, 
and the stable is therefore the direct or indirect source of many of our 
troubles. The measures necessary for holding down insect infestation 
of stable and barn yards are therefore of primary importance. But to 
emphasize this importance there must be back of every measure taken or 
recommended an argument in the form of a proof of danger if the measure 
is not carried out. 



CHAPTER II 

Some Necessary Steps in Any Attempt to Prove Insect Transmission or 

Causation of Disease * 

W. Dwight Pierce 

r ^Se study of the causation of disease is attracting far more attention 
toda^ than it ever has in the past, but it is to be regretted that there is 
not a larger proportion of this effort being directed toward locating 
the possible intermediate hosts and invertebrate carriers. 

Many excellent investigations have been carried out with all other 
phases complete, but the question of invertebrate carriers is often left 
in a very indeterminate stage. The majority of the investigations which 
have been seriously undertaken to determine invertebrate carriers have 
been conducted on other continents than ours. There is a great field for 
investigation along these lines open to the investigators in America. In 
order to stimulate such research, I have attempted in this paper to set 
down some of the necessary steps for successful investigation. 



I. COOPERATION 

I consider essential to a thorough investigation of disease trans- 
mission, the establishment of a perfect working agreement and hearty 
cooperation between one or more physicians and diagnosticians, one or 
more parasitologists, and one or more entomologists. It is not safe, 
nor does the effort bring the proper amount of credence, when one man 
attempts to do the whole work. Each phase of such an investigation 
should be handled by an expert on that phase. The day of the solitary 
investigator is past and we are now in an era of group-investigations 
which carry with them weight and conviction. Of course certain pre- 
liminary steps may easily be taken by any one member of a proposed 
group or it may be possible that they may arrive at an advanced stage 
by independent work, but the time will come in each investigation when 
a cooperation of investigators will attain the most satisfactory results. 

1 This lecture was printed in Science, n. s., vol. 50, No. 1284, pp. 125-130, August 8, 
1919. 

25 



26 SANITARY ENTOMOLOGY 

II. WHERE SHOULD THE INVESTIGATIONS OF INSECT TRANSMISSION 

BEGIN ? 

There are two distinct lines of approach to this problem of insect 
transmission. The first is to work from the known disease and to ascer- 
tain by experimentation what species of insects might be concerned in 
its transmission. The other line of approach is to make a study of all 
the insects which might be involved in disease transmission and to obtain, 
by cultures and microscopic studies, a knowledge of the parasitic organ- 
isms normally and occasionally found in these insects. Working on this 
line of investigation, one might in time of an epidemic start with insects 
visiting excreta and attempt to ascertain whether the organism of the 
disease at that time epidemic occurs in any of these insects. 

The first line of investigations would arise from public necessity and 
probably be initiated by physicians and parasitologists, or by the sugges- 
tion of entomologists. 

The second line of investigations would probably originate as problems 
assigned by a professor or head of a laboratory to students or investiga- 
tors under his direction. It is highly desirable that such studies be com- 
menced in as many institutions as practicable in the near future. Such 
investigations will include bacteriological studies, protozoological studies, 
and helminthological studies, as well as investigations of the life histories 
of the insects, and the possible connection between them and disease 
transmission. 

III. PLAN OF OPERATION 

Before starting out on any line of experiment in this subject, there 
should be written down in concise form the facts already gleaned, on the 
practical problems and the theories which have occurred to the various 
members of the group. A clearly outlined course of action should be 
made and be carefully discussed and then the various steps in the inves- 
tigations thus outlined should be read and modified to meet the changing 
views resulting from the experiments. The course of the work should 
always be kept plainly in view. Each step should be rigorously and 
skeptically scrutinized for defects. 

Inasmuch as the investigation from this point will consist of the 
answering by observation and experiment of a series of pointed ques- 
tions, I shall proceed with my discussion in the form of queries. Prob- 
ably many other vital queries will occur to the reader, but it is more 
than possible that he may overlook some of these if not set forth here. 
When each query is satisfactorily answered the problem is practically 
solved. 



STEPS TO PROVE INSECT CAUSATION OF DISEASE 27 

IV. HOW SHALL WE RECORD OUR OBSERVATIONS? 

Undoubtedly the most satisfactory method of making a large series 
of records is to use some type of loose-leaf card or sheet filing system. 
By such means one can always keep in an orderly arrangement all the 
facts so far obtained. In the case of investigations of the causation of 
a given disease, one of the most satisfactory methods which has been 
used for recording observations is to prepare a little blank booklet, which 
will fit the filing system, in large quantities, each book to represent a 
case. This book should contain pages for each phase of the question, 
with blanks covering all kinds of minutiae about this phase. The whole 
series of observations can be tabulated for each point. 

V. HOW CAN AN INSECT BE INVOLVED IN DISEASE TRANSMISSION? 

Insects may be involved in disease transmission either by the trans- 
mission of an organism or the inoculation of a toxin, or they may be an 
intermediate host in the life cycle of an organism, but not come directly 
in contact with the final host. 

1. What Kind of Organisms Can Insects Carry? 

It has been demonstrated that insects can carry bacteria, fungi, many 
types of protozoa, and many species of parasitic worms, and also that 
certain species of insects may be instrumental in carrying eggs of other 
species of insects which cause disease. 

2. In What Manner May Insect Toxins Bring About Disease? 

Many species of insects which bite inoculate at the time of the bite a 
toxin which may at times cause serious trouble. 

Some invertebrates inoculate the toxin by means of the mouth, some 
by means of a claw, some by means of a caudal appendage, others by 
means of the ovipositor. In some cases the invertebrate penetrates the 
skin with its mouth parts and as long as it is adhering, toxins are created 
which may in certain cases cause severe paralysis or death. The acci- 
dental eating of certain insects in food will cause poisoning because of 
the toxins contained in the bodies of the insects. It is believed, but not 
yet satisfactorily demonstrated, that the pollution of food by the excreta 
of certain insects may cause certain nutritional diseases. 

The presence of certain insects in the tissues causes severe irritations 
and often the formation of toxins. 



28 SANITARY ENTOMOLOGY 

3. Can Insects Themselves Cause Disease? 

Many species of insects are known to live parasitically upon the 
bodies of man and animals and by their constant sucking of blood or 
gnawing, cause skin diseases. Other species of insects habitually lay their 
eggs on or in the flesh and breed commonly or exclusively in living flesh, 
causing a destruction of the tissues. Many species of insects are depen- 
dent upon mammalian blood for the necessary nutriment to bring about 
reproduction. Some insect larvae are bloodsuckers. It is not at all 
uncommon for insect larvae to be ingested in food and for them to con- 
tinue their development in the intestines or other organs, often at the 
expense of the tissues. In some parts of the world insects are eaten as 
food by the natives, sometimes in a raw state, and it is not uncommon 
in such case for the natives to be infected with parasitic worms which 
pass their intermediate stages in the bodies of these insects, 

4. Where May Insects Obtain the Organisms which Cause {Disease? 

Disease organisms may be taken up by insects directly from the blood 
of an infected host, or they may be obtained by contact with infected 
surfaces of the body or taken up from the feces or other, excretions of 
an infected host. The insect may take up the organisms from these 
excretions either in its larval or its adult stage. 

5. How Can the Insect Transmit the Organism? 

The organism may be transmitted by the insect by direct inoculation 
through the proboscis, involving the active movement of the parasite, or 
the passive transmission of the parasite in the reflex action which takes 
place in the sucking of blood. The organism may be externally carried 
on the beak of the insect and mechanically transmitted at the time of 
sucking. It may be located in the mouth parts of the insect and burrow 
through at the same time the insect is feeding. It may be in a passive 
state on the insect and become stimulated to attack the host when it 
comes in contact with the warm body. The organism may be regurgitated 
by the insect on the body of its host and obtain entrance by its own 
activity, or by being scratched in or by being licked up by the host. 

On the other hand, the organism may pass through the' insect, and 
pass out in its feces, or in Malpighian excretions. It may be washed into 
the wound made by the sucking of the insect, by fluids excreted at the 
time of the feeding. It may remain in the feces on the host and ultimately 
be scratched in or licked up by the host. 

The organism may be taken up by the insect and never normally pass 
Out of the insect, but be inoculated by the crushing of its invertebrate 



STEPS TO PROVE INSECT CAUSATION OF DISEASE 29 

host upon the body, and the scratching of infected portions of the 
insect's body into the blood ; or may be transmitted only by the ingestion 
of the insect itself by its vertebrate host, or accidentally by some grazing 
animal. In fact quite a series of disease organisms find their way into 
their hosts because of the habit of the animals of feeding upon insects. 

6. What Is the Course of the Organism* in the Insect? 

If the organism is taken up by the insect in its larval stage, it may 
pass directly through the larva and out in its feces and may quite con- 
ceivably pass in this manner through insect after insect larva before it 
finally finds a vertebrate host. The organism may be taken up by the 
larva and remain dormant in some portion of the larva's anatomy, or on 
the other hand, it might undergo considerable development and multipli- 
cation in the larva and remain there through all the metamorphosis of 
the insect until the latter arrives at maturity, at which time development 
of the organism may begin or may continue. 

Upon being taken up in the blood by the bite of the insect, the organ- 
ism may lodge in the esophagus and carry out all its metamorphosis 
there, or in some of the organs of the head and find its way into the 
salivary glands and through the salivary secretions into a new host. 

It may, on the other hand, pass back into the gut, or into the stomach ; 
from the stomach its path may lead in many directions. It may pass on 
in its course of development into the rectum and out in the feces, or -it 
may enter the fatty bodies, or pass into the general cavity of the 
insect, or it may migrate forward into the esophagus and into the labrum ; 
and it may pass into the Malpighian tubules, or into the ovaries. 

The organism may enter the eggs and remain therein through their 
development into the larvae, nymphs or adults, and be transmitted at 
some stage of the development of the second generation. Some diseases 
can pass on even to the third generation. 

7. What Is the Course of the Organism on Leaving the Insect? 

The organism may leave the insect in the saliva and immediately enter 
the feeding puncture. It may bore through the labium of the insect at 
the time of feeding and enter the puncture. It may leave the rectum of 
the insect, or the Malpighian glands and be washed into the puncture by 
means of the secretions of the coxal glands, or some other excretions 
made at the time of feeding. It may be excreted in Malpighian secre- 
tions, or rectal feces, or regurgitated in vomit, and may lie dormant on 
the skin of the host, or on the food of the host, until it is scratched into 
the blood, or is taken into the mouth. 



30 SANITARY ENTOMOLOGY 

On the other hand, it may be possible that the organism requires 
another host after the insect, and before it reaches its final host. There 
are cases on record of the insect being the first host, and two or three 
vertebrates in succession being hosts of later stages. 

VI. WHAT IS KNOWN ABOUT THE DISEASE TO BE INVESTIGATED? 

It is a primary essential that all the workers be able to recognize 
the disease which they are trying to study and that they be fully informed 
about it, so that they may be able to grasp possible solutions of their 
problem. They will, therefore, seek first to answer the following ques- 
tions : 

1. What is the history of the disease and how long has it been 
known? How serious has it been? 

2. What is its distribution? 

3. Does it occur in pandemic, epidemic, endemic or sporadic form? 

4. In what seasons of the year is it most prevalent? 

5. Is there any apparent relationship between its distribution and 
the physical, biological or climatic features of the countries where it 
occurs? 

6. Does it affect any particular group, occupation, sex, age, race 
or nation of people, or any particular species of animal? 

7. May any wild animal be considered as a reservoir? 

8. Has immunity or difference of susceptibility been recognized and 
under what circumstances? 

9. What are the symptoms of the disease? 

10. What is known regarding immuno-chemistry and bacteriology 
of the disease? 

11. What have autopsies shown? 

12. What treatment has been designated? 

13. What is known or suspected about its causation and dissemina- 
tion ? What organisms have been connected with it ? 

14. What possible theories can be advanced to account for its 
causation and dissemination? 

A little time spent in collecting these facts may save much effort 
later. 

VII. WHAT INSECTS SHOULD BE INVESTIGATED? 

A thorough entomological study of this question may prove a valuable 
short cut to the investigation. Many insects will be eliminated by the 
entomologist before he has finished his preliminary work. He will attempt 
to answer the following and many other questions and will probably 
have to answer them to the satisfaction of all his fellow workers. 



STEPS TO PROVE INSECT CAUSATION OF DISEASE 31 

I. What insects coincide in distribution with the general distribution 
of the disease? 

£. What insects occur in peculiar habitats of the disease? 

3. What bloodsucking insects occur in the locality under investi- 
gation ? 

4. What is the relative abundance of these insects? 

5. Is there a coincidence between the season of abundance of any 
of these insects and of the disease? 

6. What insects occur in the homes, nests, or haunts of infected 
hosts ? 

7. What insects are found on infected hosts? 

8. What insects occur in the working quarters of the patients? 

9. What insects would be most apt to affect the particular group 
of hosts most susceptible? 

10. What insects breed in or frequent the excreta of the hosts? 

II. What insects are found at the food of the hosts? 

12. What insects are found at the sources of the food of the hosts, 
such as the milk? 

VHI. WHAT IS NECESSARY IN THE TRANSMISSION EXPERIMENTS? 

The investigations which have preceded will have narrowed the ques- 
tion down to certain species or groups of insects which need to be 
critically studied. All of those insects which come in contact with the 
blood or mucous membranes of the patient, or the food of the patient, 
or the feces of the patient, must be given special attention. At this 
point the bacteriologist, protozoologist, or the helminthologist finds his 
special work beginning. There will be many points which must be worked 
out by cooperation of the parasitologist and entomologist. 

Considering first the bloodsucking insects, it is necessary to deter- 
mine: 

1. Can the particular insect take up the organism with the blood? 

£. Does the organism pass into the intestinal canal or does it stop 
at some point en route? 

3. To what extent is the organism digested by the insect? 

4. In what organs of the insect can the parasite be demonstrated 
from day to day? 

5. Are any changes in the organism demonstrable? 

6. What path does the organism seem to follow in the insect's body 
from day to day? 

7. Does this movement of the organism suggest whether the trans- 
mission is by inoculation or does it suggest that the organism will pas^ 
out of the body in some of the excreta? 



32 SANITARY ENTOMOLOGY 

8. Can the organism be demonstrated in the mouth parts of the 
insect at the time of feeding? 

9. Can the organism be found in any of the excretions of the 
insect ? 

10. How long is it before the organism reaches the mouth or the 
rectum? 

11. What is the earliest date at which it can be found in the 
feces ? 

12. What is the earliest date at which infectivity of the host can 
be obtained by the sucking of the blood? 

13. What is the earliest date at which infectivity can be obtained 
by scratching in of the feces or portions of the insect? 

14*. Can infection be obtained by either natural or artificial inocula- 
tion without demonstration of the organism? 

15. Is the infective organism, contagium or virus filterable? 

16. Can the virus or organism be transmitted hereditarily by the 
insect ? 

17. At what stage of development in the second generation does 
hereditary transmission become possible? 

18. Can the organism be taken up by the immature stages, feeding 
in infected excreta? 

19. Can the organism be taken up by immature stages of an inverte- 
brate feeding on the host? 

20. How long can the immature forms of the invertebrate, infected 
by whatsoever manner, retain the organism in their system? 

21. Does the organism stay in the insect during metamorphosis? 

22. Does the organism undergo any changes preceding or following 
metamorphosis of its invertebrate host? 

23. At what stage in the metamorphosis does the insect begin to be 
infective after taking up such organisms? 

24. How long can the insect remain infected and infective? 

IX. HOW SHOULD EXPERIMENTAL INSECTS BE HANDLED? 

A large proportion of the failures in studies of insect transmission in 
the past have arisen from improper handling of the insects. The breeding 
and handling of the insects is an art in itself, just as is the culturing of 
bacteria or protozoa. In fact, there are more diverse requirements 
for handling insects of different species than can be found elsewhere in the 
animal kingdom. 

1. What must be known about the insect before beginning trans- 
mission experiments? 

The normal conditions of life of the insect must be ascertained: — its 



STEPS TO PROVE INSECT CAUSATION OF DISEASE 33 

reactions to heat and cold, moisture and dryness, disturbances, color, 
light, odor; its food, and the proper condition thereof; its methods 
of reproduction, and what food is necessary for reproduction; if soil 
should be provided, and what conditions it should be in ; if water should 
be provided, and whether this water should be alkaline or acid, clear or 
containing foreign matter, and in such case what type of foreign matter ; 
whether the water should be still or in motion, warm, moderate or cold. 

2. What type of breeding cage should be used? 

A breeding cage must be used which will most nearly enable the 
experimenter to keep the insects under control and yet reproduce essen- 
tial conditions for maintaining normal, healthy life of the insects and 
normal reproduction. Much of this information is available in entomo- 
logical literature. Many insects probably involved in disease transmis- 
sion have not been properly studied and breeding technique is yet to be 
worked out. 

3. Water is necessary in some form in practically all insect breed- 
ing. 

There are more failures to properly breed insects traceable to im- 
proper humidity, or to the lack of moisture in the proper form for the 
insects to drink. Much detailed observation may be necessary to obtain 
this important information in the case of many insects. 

4. There is a combination of temperature and humidity most favor- 
able for life, for each species, and differing from one species to another. 

5. The food of an insect must be in a particular condition in order to 
obtain normal breeding. It may require a certain degree of immaturity, 
ripeness, or fermentation. It may require a certain degree of desicca- 
tion. ' * 

Many other details must be attended to by each specialist involved 
in the investigation, and we probably have yet to see a single disease 
problem which has been completely rounded out and solved for the future 
generations. 



CHAPTER III 

A General Survey of the Needs of Entomological Sanitation in 

America * 

W. Dwight Pierce 

Notwithstanding the great amount of publicity which has been given 
the Anti-fly Campaign, one will find throughout our land a rather 
general disregard of the danger from flies. Certain newspapers keep 
the subject annually before their readers, but on the whole, public co- 
operation is slight. A few cities and communities have definitely organ- 
ized mosquito control work, and the Public Health Service has done a 
wonderful amount of work in organizing such efforts. From an ento- 
mological standpoint our nation is not sanitary. The reason lies in the 
fact that the public does not yet realize that insects can and do carry 
disease. Science has apparently not put forward the idea in such a 
manner that it has gripped the average person. Until we do this we 
cannot expect public cooperation in the attempt to put down insect- 
spread diseases. 

The problems we have to meet may be divided in several different 
manners. We may separate them into problems of municipalities, towns 
and villages, and rural communities. We may look at them from the 
standpoint of the farm, the home, the market, the factory, and the 
institution. They may be sorted out as problems of drainage, waste 
disposal, screening, animal control, etc. 

Of course we have a greater diversity of entomological control prob- 
lems in a municipality, but we also have more people who give attention 
to matters of health in a city, and who would complain against un- 
healthful conditions. On the other hand, while the problems of the rural 
community and town are fewer, the insect conditions often become greatly 
aggravated because of total carelessness as to sanitation. This careless- 
ness in small towns and farms is usually due either to ignorance or lack 
of organized effort for community betterment. 

The field of the sanitary entomologist who desires to tread virgin soil 
is therefore to solve the ways and means of obtaining better fly and 
mosquito conditions in rural communities. Educational work must be 

1 This lecture was mimeographed and circulated to the class in January and ap- 
peared in parts in The American City, for February and March, 1919. 

34 



NEEDS OF ENTOMOLOGICAL SANITATION IN AMERICA 35 

carried out which will be of such nature that it will bring results. We 
have the theories and the scientific facts but we must give the public 
practical demonstrations that freedom from insect pests means reduced 
sickness. 

Any person informed on this subject who has traveled much in rural 
sections of this country and seen the unobstructed entrance of myriads 
of house-flies to the dwellings, especially the kitchens and dining rooms, 
and then has stepped outside and within a few feet found the open privies 
breeding these flies, cannot help but feel a sickening sensation and a 
revulsion toward eating anything that the flies could have polluted. It 
is not at all uncommon in rural sections to see babies exposed to the unre- 
stricted visits of flies, and their milk bottles covered with them. The 
writer has been informed over and over by physicians in small towns 
that when infantile diarrhea or any other intestinal complaint visits a 
town it makes the rounds of every infant in the town, unless perchance, 
some mother is more advanced in her knowledge of such matters and 
keeps her baby constantly screened. When typhoid fever and dysentery 
visit towns with open privies and unscreened houses or hotels only the 
more cautious and more resistant escape. Such communities offer every 
conceivable opportunity for the spread of diseases by flies. 

THE INSANITARY FARM 

For fifteen years the writer has traveled extensively in rural communi- 
ties, principally in the Southern States, where insanitary methods, if 
existent, aggravate disease conditions because of the more favorable 
climate and greater number of maladies present. We may picture, there- 
fore, a few of the conditions which have been repeatedly seen in these 
travels, in order the better to show the problems to be met. We shall not 
claim that these pictures represent the predominant, or the usual, or the 
average condition. Let it suffice that they exist sufficiently often to make 
them worthy of serious attention. 

The farm we will describe has been seen countless times. The house 
has no screens on the windows, in fact, often has no window panes, or 
may have wooden windows which are open all day. The house is one- 
storied with an outside chimney, and an open fireplace. The chimney and 
fireplace offer excellent day hiding places for mosquitoes, which are 
abundant if there is a slough or bayou nearby. The house is built on 
stumps or pillars raised above the ground. The pigs and chickens, dogs 
and cats, wander freely underneath. The house has a great open hall- 
way through the middle, separating the bedrooms from the living rooms. 
On account of the numerous flea-breeding animals which pass under the 
house, fleas are not at all uncommon in the house. The well is usually 



36 SANITARY ENTOMOLOGY 

open and built into the back portion of the porch. Mosquitoes breed in 
it. There is a poorly constructed, dilapidated privy for the women not 
far from the house, but the men have none, or if they do, it is not fit to 
enter. They usually defecate in the open, in the fields or draws, or in a 
woodland patch. The barn is roughly constructed. The manure is piled 
in a great pile beside the barn, and breeds multitudes of flies. The stable 
floor is urine- and manure-soaked and affords excellent fly-breeding 
quarters. 

Naturally, I have described the worst common type of farm, because 
on this must be built the structure for better sanitation in farm life. 
In many cases a large number of such places may exist on a single 
large plantation, for the use of the tenants. In such cases a single man 
is responsible, who himself lives in a house with all modern sanitary 
conveniences. 

The problem of the sanitarian and the sanitary entomologist is to 
prove to the individual farmer and to the planter landlord the financial 
value of better sanitation. The planter must be shown that inasmuch 
as the efficiency hours of his tenants are increased, in proportion will 
their products be increased, and in like manner his rental, especially 
where the rental is based on certain proportions of the crop yield. He 
must see that reduction of mosquitoes means reduction of malaria inci- 
dence, that reduction of flies reduces the incidence of typhoid, dysentery, 
diarrhea, and other intestinal complaints, and that as the sickness rate on 
the plantation is decreased the labor output is increased. 

It will do us no good to theorize if we do not set down clearly the 
ways and means of accomplishing this greater farm output by reducing 
fly and mosquito breeding. In the present course of lectures will be 
found the proofs which have accumulated against ^hese various insects, 
brief statements of how these insects live, and detailed plans of the 
approved methods of control. Fortified with this ammunition and more 
which he will personally gain, the sanitary entomologist must fight for 
better sanitation. 

HOW TO IMPROVE FARM SANITATION 

At this time, however, we may in brief state a few measures which 
should be taken on every farm in order to accomplish greater farm labor 
efficiency and improve the health of the household and of the animals. 

1. The windows and doors should be screened against flies and 
mosquitoes. During the months that fires are not used the chimneys 
should have a screen over the top and the fireplace screened. If wire 
screening cannot be afforded, mosquito bars can be used. In the majority 
of cases the expenditure of the necessary amount of money to properly 



NEEDS OF ENTOMOLOGICAL SANITATION IN AMERICA 37 

screen the place will be offset by a greater reduction in doctor's bills for 
the women and children at least. 

2. Where there are many children passing in and out flies will get 
in. The children should be taught to use fly swatters. No flies should 
ever be allowed to remain in the kitchen and dining rooms. Flies which 
visit food will deposit on it any disease organisms they have picked up. 
If the water is pure, the fly is about the only common means of conveying 
intestinal diseases to the family. 

3. Unless the babies and small children are kept indoors in screened 
rooms, the helpless children should have a mosquito bar over the carriage 
or basket so as to protect them from flies. This is absolutely essential 
if there is any sickness in the neighborhood. 

4. There should be installed sanitary q)it or bucket privies such as 
are recommended by the Public Health Service. Both men and women 
should be provided with such, and it should be a»rule of every farm that 
indiscriminate defecation is absolutely forbidden. As many farms are 
quite large the most feasible plan would be to place at various places 
over the farm where they would be most convenient and best protected, 
some type of latrine, such as is used by armies, or better still a perma- 
nent privy. 

5. The well should be kept covered to prevent as far as possible 
mosquito breeding and contamination. 

6. The foundations of the house should be boarded up to prevent 
the access of animals and to eliminate a favorite mosquito hiding place. 
The ground around the house should be so drained that water will not 
flow under the house except in case of 'heavy rains, and in such cases will 
quickly drain off from under the house. 

7. All ditches, ponds, streams, and bayous on the farm should have 
the banks kept clear of obstructions to the free flow of the water. There 
should not be any tree stumps, trees, roots, weeds, or logs in the stream. 
The banks should not have overhanging ledges, or puddle pits. Per- 
manent ponds and lakes might be stocked with mosquito-eating fish. 
Places which habitually form puddles after rains should be filled and 
drained. 

8. The barns should have hard packed dirt floors or cement floors. 
All manure should be removed daily from the barn. If possible the 
manure should be spread while fresh on fields lying fallow. Otherwise the 
manure should be piled in tightly packed stacks or on platforms over a 
cement basin containing water, in order to drown the fly larvae migrating 
for pupation. 

9. The garbage should be fed to pigs, preferably in sanitary feeding 
stalls as described by Bishopp in the lecture on the control of flies in 
barn yards, pig pens and chicken yards (Chapter XI). 



38 SANITARY ENTOMOLOGY 

10. State Boards of Health should follow the California plan and 
forbid the marketing of fruit dried on farms with open sewage, or where 
exposed to visits of flies. 

THE INSANITARY TOWN 

In these same travels in which so many insanitary farms were seen, 
the writer has sojourned in or passed through many towns which might 
be described as follows : The streets are unpaved and are littered from 
one end to the other with papers, cans, and the accumulation of months of 
manure droppings, and are altogether filthy and unattractive. The 
removal of trash is nobody's business. The grocery stores and meat 
markets are unscreened and have open doors. The food is covered with 
flies. Farmers drive up and buy a side of salt pork or other meat, 
throw it into the pit of their wagon, uncovered, and drive down the 
dusty road, with a swarm of flies hovering over the meat. The small 
lunch rooms where the visiting farmer eats his noon or evening repast 
are dirty and full of flies. The stores have privies in the rear which 
are filthy and an offense to any decent person. Flies abound. Chickens 
and pigs wander unrestricted through the streets and are often found 
feeding under the privies. The hotel dining rooms and kitchens are 
always full of flies and are usually but a short distance from filthy 
privies, and flies are constantly passing back and forth. Cockroaches are 
served in the food and wander unrestricted everywhere. The bedding is 
often unclean and has been slept in by some one else. Bedbugs are not 
uncommon. The water pitchers contain mosquito wrigglers. The cis- 
terns behind each house are unscreened, and contain rain water, full of 
mosquitoes. The livery stable has great piles of manure in the stable 
yards and sometimes right out on the sidewalk. 

Sometimes the town is a little bigger and the people have become more 
civilized and installed interior plumbing, which empties the sewage into 
a ditch which runs down to a stream from which cattle drink, or quite 
often this sewage empties into the gutter on the street and fills the air 
with filthy odors. Such is not an uncommon thing in America. Only 
a few years ago we could have pointed out quite a number of cities in the 
100,000 class with open sewage. 

These small towns are often rat infested, and one can easily see 
the danger should an outbreak of plague, which is transmitted by the 
rat flea, get a start in such a town, by the advent of a plague infested 
rat. 

HOW TO IMPROVE SANITATION 

1. Organize the community for better sanitation, and call in an 
expert of the Public Health Service, which is giving a great deal of 



NEEDS OF ENTOMOLOGICAL SANITATION IN AMERICA 39 

attention to cooperative health work. In Russia, such organizations were 
springing up all over the land before that country became submerged in 
its present chaos. 

2. Conduct a health publicity campaign. 

3. Teach better sanitation in the schools and organize the children 
for clean-up work. 

4. Require the screening of all stores selling food, and of all hotels 
and restaurants dispensing food. Do not allow food to be handled in 
such a way that it will attract great quantities of flies. 

5. Require private stables to place manure in fly-tight boxes and 
to have same removed every 7 to 10 days. 

6. Require livery stables to remove all accumulations of manure 
daily from the town limits. 

7. Require the burning, feeding or removal of all garbage twice a 
week from homes and daily from hotels. 

8. If garbage is hauled away and dumped the town should arrange 
for its daily incineration. 

9. Require throughout the town limits, depending upon conditions, 
either sanitary plumbing and sewer connection, or sanitary box or pail 
privies. Do not allow pit privies or insanitary ones of any type. Do 
away as soon as possible with open sewer drainage, installing sewer pipe. 
Install sewage septic tanks of size adequate for the town. If there are no 
sewers laid it may be possible to arrange for individual installation of 
simple septic tanks. 

10. Do not allow pigs and chickens to have access to privies. 

11. Do not permit general roving of pigs, stock, chickens, etc., on 
the town streets. 

12. Keep all ditches and waterways in the town free of obstruction, 
and if mosquitoes are breeding, have an oiling squad. 

13. Fix strict penalties against defecation on streets, alleys, and 
vacant lots. 

14. Install a town comfort station for strangers and people from 
the country. 

SANITARY PROBLEMS OF CITIES 

The sanitary entomological problems are multiple in large cities, and 
such that it would be an excellent practice to employ at least a consult- 
ing entomologist in all large cities. As a matter of fact many cities 
should have quite a corps of practical sanitary entomologists engaged 
primarily for this type of work. 

City markets where meats, fish and all kinds of vegetables and produce 
are exposed for sale, are very attractive places for flies, and in many 
large cities there is gross neglect along these lines. 



40 SANITARY ENTOMOLOGY 

Sanitary inspectors need to exercise considerable vigilance in checking 
up obedience to ordinances relating to removal of trash, garbage, manure, 
excreta ; installation of sewage or sanitary privies ; proper sanitation 
among construction gangs ; nuisances arising from stables, factories, 
sewage and garbage disposal plants, packing houses, stock yards, etc. 
Many manufacturing plants have waste products which are very attrac- 
tive to insects. Insect conditions in restaurants, boarding houses and 
hotels should be frequently checked up. 

Anti-fly and anti-mosquito propaganda should be conducted annually 
in every city until the people are so well educated to the necessity thereof 
that propaganda will no longer be necessary. 

The sanitary department of large cities should directly supervise 
mosquito suppression within its bounds. 



ENTOMOLOGICAL REQUIREMENTS OF MUNICIPAL SANITATION 

■ The following points should be covered by ordinance in all large cities 
desirous of obtaining satisfactory sanitation. Not enough attention 
has been given by city health authorities to the insect side of their 
sanitary problems. 

1. All foodstuffs, which are eaten raw, all raw meats, fish, birds, 
cooked foods, bread, cheese, dried fruits, etc., must be kept under cover 
of glass or screen or otherwise protected from insects, in all markets, 
stores, street stands, hotels, restaurants and boarding houses. Flies must 
not be allowed to congregate around food stalls. Cockroaches must be 
eliminated from all hotels, restaurants and boarding houses. Foods 
infested by insects should be subject to condemnation and destruction. 
Insect contamination of food is dangerous. 

2. Hotels, public institutions, and lodging houses shall be required to 
keep their premises free of bedbugs. Bedbugs carry disease. 

3. All school children shall be inspected at the beginning of each 
new school year for head lice, and oftener if circumstances warrant. In 
case the children are infested they should be isolated and sent to some 
clinic where they can be freed of the lice. All prisoners, patients in 
hospitals, and applicants at municipal lodging houses should be in- 
spected for head, body, and crab lice, and if infested should be bathed and 
their clothing condemned or cleaned. Lice carry many diseases and every 
opportunity should be taken which will enable the authorities to reduce 
their incidence. 

4. All livery stables shall be required to remove all manure to the 
country daily, unless specified places for dumping are set aside. All 
private stables should be provided with a fly-proof box or a maggot- 



NEEDS OF ENTOMOLOGICAL SANITATION IN AMERICA 41 

trap platform for the storage of manure and should have the manure 
removed at least every 10 days. 

5. Garbage should be removed daily from all places where it accu- 
mulates in large quantities, and two or three times a week from private 
residences. All garbage awaiting removal should be kept in closed 
cans. Garbage must not be dumped within the city limits unless it is 
dumped on incinerators where fires will soon consume it. These require- 
ments are necessary to keep down fly breeding. 

6. Tin cans, bottles, and receptacles which will hold water, must 
not be allowed to accumulate in back yards, alleys or vacant lots, nor 
may they be dumped within the city limits or near residential sections 
in the suburbs, because they furnish excellent breeding quarters for 
mosquitoes. 

7. The city should be connected for sewers as far into the suburbs 
as practicable, and all suburban properties not so connected should be 
required to install fly-proof cesspools, or septic tanks, or to arrange by 
neighborhoods for independent sewage with a common septic tank; or in 
the absence of water and necessary plumbing, to install sanitary privies, 
and be required to have all excreta removed once a week to an incinerator 
or other type of refuse disposal plant. Open vault privies should not be 
permitted in the city. Indiscriminate defecation on streets, alleys, vacant 
lots, etc., should be strictly forbidden and punishable by law. 

8. Packing houses, candy factories, syrup factories, and all other 
manufacturing institutions producing food products should be required 
to screen windows and entrances, and to use fly traps in such a way as 
to minimize to the utmost the access of flies and other insects to the food 
products. Especial attention should be given to the prevention of insect 
breeding on such premises. 



INDUSTRIAL SANITATION 

Many industries have important entomological sanitary problems in 
the preservation of their products from insect contamination and in the 
efforts to conform to sanitary regulations. There are many times when 
they would be able to use the services of a consulting sanitary entomologist 
to advantage. 

The keynote of industry today is the prevention or utilization of 
waste. Insect depredations on food products cause waste because the 
public does not want polluted food, and because sanitary inspectors are 
becoming more and more alive to the menace to health from insect pol- 
luted foods. 

It is not generally understood that the presence of weevils and worms 
in cereal foods may do more than destroy the food. The evidence is 



42 SANITARY ENTOMOLOGY 

growing against these insects from the sanitary standpoint. Some of 
these insects contain substances in their bodies which are highly toxic, as 
for instance Sitophilus granarius, the granary weevil, contains the 
poisonous substance cantharidin. There are numerous instances of the 
sickening of animals from eating weevily grain. Still more important is 
the fact that where grain is accessible both to rodents and insects, certain 
parasitic worms pass out in the feces of the rodent in the egg stage, 
are eaten by the insect larvae in the grain, pass part of their life cycle 
in the insect, and the insect is then possibly eaten by a rodent, in which 
the worm completes its life cycle; or sometimes in our breakfast foods 
we eat these parasitized insects and become infected with the worms. For 
example, the rat tapeworm, Hymenolepis dimmuta (Rudolphi) infests 
various species of rats, but sometimes is found in man. Joyeux has 
proved that its commonest intermediate host is the meal moth, Asopia 
farinalis, which becomes infected by eating the tapeworm eggs, in the 
larval stage. Grassi and Rovelli found the cysticercoid in the larva and 
adult of this moth and also in the earwig, Anisolabis annulipes and the 
beetles Akis spinosa and Scaurus striatus. Joyeux found that the adults 
of the granary beetle, Tenebrio molitor, easily took up the eggs. A 
cysticercoid or larval stage resembling the mouse tapeworm Hymenolepis 
microstoma (Dujardin) has been found by Grassi and Rovelli in the 
beetle Tenebrio molitor. 

The whole problem, therefore, of the control of stored food product 
insects is of vital importance to the manufacturers of food. 

Syrup factories, sugar mills and refineries, ice cream factories, cream- 
eries, and candy factories offer great attractions to flies which may 
alight on the exposed products and deposit with their feet, or in their 
vomit or excreta, germs of disease taken up elsewhere, perhaps days 
before when the fly was a larva breeding in excrement, and these germs 
may find the sweets excellent culture media for extensive growth. Extraor- 
dinary means must be devised to keep flies away from such products. 

Packinghouses offer abundant attractions to many kinds of insects, 
many of which are serious disease carriers. 

Railroad trains are the means of conveying from place to place 
disease-carrying mosquitoes, flies, roaches, fleas, lice, bedbugs, and mites. 
Fumigation of railway cars is an essential entomological control measure. 

Dairies are often found to be the foci of the spread of typhoid fever, 
and knowing the propensity of the house fly we can see how readily it 
can carry the organisms from the stools of a sick person to the milk 
pails in the dairy. There needs to be rigid control of flies in all dairies. 

These are but examples of many industries which have problems in 
sanitary entomology. 



CHAPTER IV 

A General Survey of the Seriousness of Insect-Borne Diseases to Armies * 

W. Dwight Pierce 

As this course of study is directed primarily toward obtaining a 
thorough knowledge of the relations of insects to diseases of men and 
the measures which must be taken to prevent these diseases, it is eminently 
proper for us to make a survey of the insect problems which confront the 
greatest aggregations of men, the modern army. From a study of mili- 
tary sanitation methods we may learn much which we need to know in 
practical municipal problems. Military methods are based on the neces- 
sity of quick returns and emergency efficiency, from which are built up in 
permanent establishments more perfect measures. 

The discussion of military entomology immediately falls into two very 
distinct lines: first, the army training and concentration camps, and 
second, the active service camps and battle conditions. 

Before the location of the average training camp, we may assume 
that it is possible to deliberate more or less on the desirability of one or 
more sites and that in a general way drinking water and general health 
conditions are considered. Not infrequently some other consideration 
will outweigh sanitation, as when it is considered essential to place a camp 
near a certain city or on a certain waterway or railway. In such cases 
of expediency, we are quite likely to find sanitation a serious problem 
from the outset. 

The camp site is selected because of some important reason. 
From an entomologist's viewpoint a number of outstanding questions 
immediately arise as to this site. Is the ground open or wooded, level or 
sloping and well drained? Are there water holes, running streams, or 
swamps in the camp area or nearby? Are there farmhouses, stables, 
or other buildings on the site and what is the entomological situation in 
these buildings? What disease-carrying insects are naturally breeding 
about the camp site? If there has been any contagious disease of man 
or- animals in the community before the camp was located, the entomolo- 
gist's concern is the greater. He should if possible learn the focus of 

1 This lecture was originally presented May 27, 1918, and distributed the same day. 
It has been revised for the present edition. 

43 



44 SANITARY ENTOMOLOGY 

that disease and the insect conditions of that focus. The original health 
conditions on the site may have a distinct bearing on later events. 

Often the first arrivals at the camp site are contractors with multi- 
tudes of laborers and animals collected from everywhere, and from every 
stratum of society. There are few hygienic arrangements for these men. 
In fact, the contractors are aiming to obtain as large profits as possible, 
and therefore hold down the expenses for sanitary waste disposal. Some 
among these laborers are almost certain to bring lice, bedbugs, fleas, and 
possibly also scabies mites, on their bodies and clothes. Thrown together 
indiscriminately in hastily constructed barracks, there is soon a general 
distribution of vermin. Their animals are quite likely to be infected with 
scabies mites and possibly other mites, and with bots and ticks. The 
undisciplined assembling of many animals and carelessness about manure 
disposal offers great attractiveness to all flies and insects attracted by 
animals. It is probable that many dogs accompany the laborers and 
contribute their quota of fleas. It is almost impossible with crude, unedu- 
cated laboring men to get them to maintain sanitary conditions. Indis- 
criminate defecation, the scattering of garbage, the accumulation of 
manure, personal uncleanliness, all contribute to make contractor camps 
sanitary sore spots. 

Sooner or later the sanitarians arrive on the spot, very likely with 
a squad or company of raw untrained labor troops, and the clean-up 
begins. We can expect a constant lack of coordination between the 
military and the civilian. As for example, at one camp the sanitary 
officers had constructed drainage ditches to carry off surplus standing 
water, but the laborers persisted in throwing scraps of wood, underbrush 
and waste into the ditches so that they were of no avail, or rather so that 
they formed traps for water pools. 

During the transition period when the camp is part civilian and part 
military there will be two very different types of conditions existing 
side by side, one good, one bad. Of course the army sanitarians have 
supervision over these civilian camps, but they find difficulty in enforcing 
sanitation. 

When a camp is placed like Camp Humphreys, Virginia, on a tongue 
of land between two shallow bays of water that are known to fill up with 
vegetation, and which furnish breeding places for millions of mosquitoes, 
and with typical swamp lands at the heads of these bays, we may readily 
see that the task of the sanitary officer is not an easy one. These bays 
are moreover at tidal level and the daily fluctuations of the water add 
complications to the drainage problem. Each individual camp, wherever 
located, will present its own type of problems, and necessitates an early 
and thorough entomological survey. 

The tremendous speed of construction and the" rapid arrivals of fresh 



SERIOUSNESS OF INSECT-BORNE DISEASES TO ARMIES 45 

contingents of troops and animals in a new army camp make the first 
months of the entomological sanitarian very busy ones. Common sense 
is one of the primary essentials in meeting the exigencies of the situation. 
The possibility of mosquito breeding must be kept at a minimum in spite 
of temporary drainage, multitudes of borrow pits, tree stumps, fire-water 
barrels, etc. A system of manure, garbage, refuse, and fecal disposal 
is of necessity hastily devised and must keep pace with the increasing 
numbers of men and animals. This waste disposal is handled by special 
units and the sanitarian acts only in an advisory capacity. He needs 
therefore to be very vigilant in his inspections. Army camps nowadays 
grow in such marvelous proportions that past experiences are of little 
avail. The man on the ground must be well versed in the principles of 
entomological sanitation and must use his judgment for all it is worth. 

The constant accessions in troops and raw recruits call for constant 
scouting and prophylaxis to prevent admission of vermin. The work 
against vermin almost necessitates a specialist to take care of it alone. In 
fact it were best if three entomologists were located in each camp, one 
looking after the suppression of water and moist earth breeding insects, 
one looking after the suppression of fecal, waste, and manure breeding 
insects, and the third handling the vermin of the person and the barracks. 

So serious is the vermin problem in all armies that elaborate measures 
have to be taken to combat it. The Germans developed great vacuum 
tubes that will contain an entire railroad coach. The Russians, and then 
other nations, developed bath trains sufficient to handle the cleansing of 
thousands of men a day. The Russians and Roumanians developed sod 
houses for heat sterilization of clothing. Heat and steam sterilizing plants 
of many types have been devised. A tremendous amount of experimen- 
tation has been directed toward chemical cleansing of the clothing. 

The destruction of waste is such an acute problem that many types of 
incinerators have resulted (see figs. 1, 2, 3), but as a camp becomes 
permanently organized the sewage system does away with many of the 
early difficulties. Permanent incinerators, well kept drainage systems, 
organized removal of the manure, and disposal of garbage by the quarter- 
master's department, systematic inspection of quarters and grounds, and 
systematic bathing and cleansing of clothing, characterize the perfectly 
adjusted sanitation of a permanent camp. Every large army camp 
has its remount camp and company stables. The farther these stables are 
located from the soldiers' barracks the better will be the fly conditions 
in the living quarters of the men. 

The actively engaged army, however, presents entirely different con- 
ditions. There is no possibility of developing sewage systems, but tem- 
porary latrines must be substituted (see figs. 4, 5, 6, 7). Manure and 
garbage cannot be farmed out to contractors, but must be disposed of 



48 



SANITARY ENTOMOLOGY 



metal t, p 




Fig. 1. — Cross section of Mann's hillside incinerator, used at U. S. Marine Camp, 

Quantico, Va. (Mann). 



tuaavvo 




Fig. 2. — Modification of Mann's hillside incinerator, adapting it to level ground (Mann). 



totidre&rft 



wioKt Me 



^rtiwdUt cms* Wbrt 



liquid fejuifccdn 
wrvn ptrferATtd 




Fig. 3. — Small incinerator of the Ferguson type, for use of small units, and capable 

of transportation (Mann). 



SERIOUSNESS OF INSECT-BORNE DISEASES TO ARMIES 47 




Fig. 4.— Straddle trench latrines, 1 foot wide, 2 feet deep, 3 feet long, for field opera- 
tions at temporary locations (Mann). 




Fig. 5.— Covered pit latrine level with ground, a semi-permanent type (Mann), 

Z 




Fig. 6.— Garbage can with top converted into portable urinal for use in company street 

at night (Mann). 



48 SANITARY ENTOMOLOGY 

by hastily built incinerators, or the manure stacked and treated to kill 
flies. Ditches and standing water cannot be drained. They must be 
treated to kill insect life in them. Temporary hospitals abound and 
must be protected from flies and vermin. The men sleep out of doors 
or in scanty shelters, even in pig pens, barns, etc., wherever they can 
find shelter in inclement weather. 

Insect infestation in these must be reduced to a minimum. When lice 
abound, hastily constructed devices must be installed or the clothing 
treated by chemicals. The trenches and dugouts have to be sprayed with 
creosote oils to keep away flies and kill vermin. Terrible stenches arise 
from dead bodies and these must be buried or treated to prevent fly 
breeding. ' In other words, everything here must be done hastily but 




.CROSS SWTJGtt 
Fig. 7. — Urine soakage pit, in cross section (Mann's modification from Lelean). 

effectively, for tomorrow the work may have to be done all over some- 
where beyond or behind. The larger the body of men assembled and the 
greater the carnage, the more serious the diseases of all kinds and 
especially those carried by insects. 

In the great European War the greatest diseases were those borne 
by lice. In fact there is plenty of evidence that louse-borne diseases 
have been among the worst in many wars of the past. Three serious 
diseases which ravaged the trenches are carried onty by lice, — typhus 
fever, trench fever, and European relapsing fever. Millions of the 
Serbian nation were wiped out by typhus fever. The Roumanian nation 
was swept by typhus and relapsing fever. Russia, Germany, Austria and 
France suffered terribly from these louse-borne diseases. Trench fever 
spread back from the trenches into the cities. And yet all of these 
diseases can be controlled absolutely by suppressing the lice. It is easy 
to see how serious it is if a case of any of these diseases enters the 



SERIOUSNESS OF INSECT-BORNE DISEASES TO ARMIES 49 

trenches. The lice spread from man to man, and they are noted for 
leaving a man with feverish conditions for a normal man. 

Another disease which has been especially bothersome in the trenches 
is scabies. Both horses and men are seriously afflicted with this mite 
disease, and special veterinary hospitals were constructed in France solely 
for handling horse scabies. 

In malarious countries where mosquitoes are breeding in great num- 
bers, malaria is a very serious camp and army problem. Campaigns in 
tropical countries are endangered often by yellow fever, dengue and 
filariasis, which are also mosquito-borne diseases. 

The troops engaged in Asia and some parts of the Mediterranean lit- 
toral had to contend with the possibilities of plague outbreaks. Troops 
engaged in the African campaigns had to deal with trypanosome and 
spirochete diseases. Along the Mediterranean littoral pappataci fever 
is to be seriously considered. For example, a detachment of the British 
Army in Egypt was suddenly attacked by an outbreak of this disease. 

We are all familiar with the disaster of our Spanish-American War 
in which so many thousands were carried away by typhoid fever, dysen- 
tery and diarrhea, all fly-borne diseases. In the present war, to these 
must be added Asiatic cholera, also borne by the fly. 

The great quantity of carcasses on the battlefield gives rise to myriads 
of flesh and carrion flies and as a consequence of the habit of these 
flies of attacking wounds of living people, there were many cases of 
human as well as animal anthrax in the European War. 

These are only the more important army diseases carried by insects. 
One of the greatest dangers to troops in active service lies in their 
moving into countries with obscure or little studied diseases, or diseases 
against which the men have had no chance to develop immunity. 



CHAPTER V 

Relation of Insects to the Parasitic Worms of Vertebrates 1 
B. H. Ransom 

The only important part insects are known to play in the propagation 
of parasitic worms that affect human beings and other vertebrates is 
that of true intermediate hosts necessary to the existence of the parasites 
in some of their stages of development. Observations have been recorded 
in the literature showing that flies and other insects may swallow the 
eggs of various parasites of man such as hookworms, whipworms and 
other nematodes in whose life history no intermediate hosts are required, 
also the eggs of tapeworms in whose normal life history it is known that 
insects are not concerned, for example, Taenia saginata, whose inter- 
mediate host is the ox. It has been supposed that insects may thus act 
as mechanical carriers for such parasites, but as a matter of fact definite 
evidence of the importance of insects as mechanical carriers of the eggs 
or larvae of parasitic worms has not yet been brought forth. On the 
contrary there are reasons to suppose that in some cases at least the 
swallowing of the eggs or larvae of parasites by insects that can act 
only as mechanical carriers and not as intermediate hosts, reduces rather 
than increases the chances of the young parasites continuing their 
development and reaching a host in which they can become mature. 
Among the parasitic worms affecting man and other vertebrates it is 
those forms requiring intermediate hosts, so-called heteroxenous parasites, 
that are of special interest so far as insect transmission is concerned. 
The monoxenous parasites, or those requiring no intermediate host, may 
practically be left out of consideration, with the admission that the 
mechanical carriage of monoxenous parasitic worms by insects may in 
the future be proved to have an importance not yet demonstrated. 

A complete demonstration of the part played by an insect in the life 
history of a given species of parasite is often a difficult matter. The 
animal which serves as the final host may be subject to infection not 
only with the species of parasite under investigation but also with other 
species liable to be confused with it in some of its stages. The insect 

ir rhis lecture was read to the class on December 16, 1918, and distributed January, 
1919. It has been revised up to date. The names of insects have been revised by 
the editor. 

50 



RELATION OF INSECTS TO THE PARASITIC WORMS 51 

may likewise harbor parasites other than the one that is being studied. 
The possibilities of confusion and of the entrance of extraneous factors 
into the problem are so many and so varied that in most cases it is 
only after the most rigorously controlled experiments, combined with 
careful comparative studies of the successive stages of the parasite, that 
conclusions may safely be drawn. Furthermore, in working out the life 
history of a parasitic worm it is not sufficient to prove that insects of a 
certain species can act as intermediate hosts under experimental condi- 
tions. Some species of parasitic worms are able to develop in more than 
one species of insect, and the fact that a certain parasite can develop in 
a certain insect does not necessarily mean that under natural conditions 
the species of insect in question serves as the intermediate host of the 
parasite. For example, one of the common parasites of sheep and cattle 
is able to pass through its larval stages in cockroaches. These insects 
become readily infected if the eggs of the parasite which occur in the 
feces of the final host animals are fed to them. Under natural conditions, 
however, cockroaches do not ingest the feces of sheep and cattle, nor are 
they found in places where they are likely to be picked up by sheep and 
cattle. Besides cockroaches, various species of dung beetles have been 
shown to be capable of acting as intermediate hosts of the parasite in 
question, and it is evident that these insects are the natural intermediate 
hosts. Unlike cockroaches they have plenty of opportunity both of 
becoming infected and of passing on their infection to the final hosts. 

A more or less intimate environmental relationship between the insect 
host and the final host generally exists in the case of parasites transmitted 
by insects. In a number of cases the insects are coprophagous and also 
likely to be ingested by the final hosts, as in the instance just cited. 
Another highly interesting group of cases is that in which the insects 
are ectoparasites on the final hosts, or bloodsuckers that periodically 
visit them, and thus have particularly favorable opportunities for becom- 
ing infected with parasitic worms harbored by the animals they attack 
and in turn reinfecting the latter. 

MODE OF INFECTION OF INSECT HOSTS 

As already stated the part which insects may take in the propagation 
of parasitic worms of higher animals is that of intermediate hosts, in 
which certain larval stages of the parasites are passed before they are 
ready to enter the bodies of their final or definitive hosts in which they 
develop to maturity. The way in which the insects become infected varies 
with different species of parasites. In the case of some species which 
live in the alimentary tract of the final host the eggs or larvae are dis- 
charged from the body of the host in the feces. Coprophagous insects 



52 SANITARY ENTOMOLOGY 

swallow the eggs and if they are suitable intermediate hosts for the 
parasites the young worms go through several developmental stages and 
finally within the bodies of the insects reach a stage in which they are 
ready to be introduced into the body of the final host. Certain parasites 
whose adult stages live in relation with the blood vessels of the final host 
discharge their young into the blood stream whence they may be ingested 
by bloodsucking insects in whose bodies they undergo development to a 
stage infective for the final host. Aquatic insects may swallow free-living 
larval stages of parasites, or may be actively attacked by larval para- 
sites which gain entrance to their bodies by penetrating the cuticle. 
These insects may in turn be eaten by other insects and the infection thus 
passed on to them. 

In some cases the parasites may be taken up by insects or enter 
their bodies during an early stage of development of the insects and 
persist in later stages. Infection may thus occur during one stage of the 
insect but the development of the parasite to a stage infective for the 
final host may not be completed until after the insect has reached a later 
stage. Thus flies become infected with a certain parasite of the horse 
during the maggot stage, but the young parasites do not become suffi- 
ciently developed to be returned to the final host until the flies have 
reached the pupal or adult stage. 

MODE OF INFECTION OF VERTEBRATE HOSTS 

Parasitic worms that have insects for intermediate hosts reach 
their final hosts in various ways. In the case of some species the insect 
hosts are swallowed either as the habitual food of the final hosts, or 
incidentally with food or drink. In other instances the young worm may 
have already escaped from its insect host before it is taken in with food 
or drink by its final host. The cases of accidental infection with horse- 
hair worms not normally parasites of human beings are likely to have 
happened in this way. The parasites of which bloodsucking insects are 
intermediate hosts may be introduced into their final hosts as a result of 
the escape of the larval parasites from the insects at a time when the 
insects are drawing blood. Commonly the larvae burst through a weak 
spot in the cuticle of the insect and then burrow into the skin of the 
final host. 

SPECIES OF WORMS FOUND IN INSECTS 

The parasitic worms of the higher animals in whose life history insects 
and insect-like organisms play a part, belong to two large zoological 
groups, Plathelminthes and Nemathelminthes. The former may be sub- 
divided so far as concerns parasitic forms into Cestoda, or tapeworms, 






RELATION OF INSECTS TO THE PARASITIC WORMS 53 

and Trematoda, or flukes ; the latter into Nematoda, or roundworms in 
the restricted sense, Gordiacea, or horse-hair worms, and Acanthocephala, 
or thorn-headed worms. 



CESTODA OR TAPEWORMS 

All tapeworms whose life history has been well established require an 
intermediate host, and are thus heteroxenous parasites. A typical life 
history of a tapeworm is as follows : The adult lives in the intestine of 
the final host. The eggs pass out of the body of the infested animal in 
the feces. The feces or food or drink contaminated by them are swallowed 
by an animal that can act as an intermediate host. The eggs thus 
reaching the intermediate host hatch in the alimentary tract and the 
embryos set free migrate into nearby or remote tissues of the body, 
developing finally into an intermediate stage, commonly of the type known 
as a cysticercoid, in the case of those tapeworms whose intermediate stages 
occur in insects. Having reached this stage further development of 
the parasite awaits the time when the intermediate host or infested por- 
tions of its body are swallowed by an animal that can act as the final host, 
whereupon it resumes its development and, becoming mature, completes 
the life cycle. About 100 species of tapeworms are known whose adult 
stages occur in man or domestic animals. Four of these, Dipylidium 
canmum (the double-pored tapeworm of the dog, cat, and man), Hymen- 
olepis diminuta (the yellow-spotted tapeworm of rats, mice, and man), 
Hymenolepis nana (the dwarf tapeworm of rats, mice, and man), and 
Choanotaznia infundibulum (one of the tapeworms of the domestic fowl), 
have insects as intermediate hosts, with the possible exception of the dwarf 
tapeworm, in whose life history the part played by insects has not been 
definitely determined. 

Dipylidium caninum (Linnaeus, 1758) feailliet, 1892 

This tapeworm, sometimes called the double-pored dog tapeworm, is of 
very common occurrence in the small intestine of dogs and cats, and of 
occasional occurrence in human beings. Its larval stage (cysticercoid) 
occurs in the biting dog louse [Tricliodectes latus (canis)] as deter- 
mined experimentally by Melnikov (1869), and in fleas (Ctenocephalus 
canis, C. felis, and Pulex irritans). Fleas apparently are the usual 
intermediate hosts. Grassi and Rovelli (1888, 1889) followed the various 
stages of larval development in adult fleas, from the hexacanth embryo 
to the fully developed cysticercoid, and as they failed to find the parasite 
in larval fleas concluded that only adult fleas can act as hosts. Recently, 
however, Joyeux (1916) has reached the conclusion that adult fleas 



54 SANITARY ENTOMOLOGY 

are unable to swallow the eggs of the tapeworm. He finds that larval 
fleas readily swallow the eggs; these hatch in the intestine of the insect, 
and the embryos thus released penetrate into the body cavity. They per- 
sist in the hexacanth stage until the transformation of the flea into the 
adult, after which they proceed with their development and in a short 
time reach the cysticercoid stage. Infection of the dog, cat, or human 
being occurs naturally as a result of swallowing infested fleas. Fleas 
are exposed to infection owing to the fact that their larvae live in an 
environment likely to be contaminated by the feces of infested dogs or 
cats. The eggs of the tapeworm as passed in the feces are grouped in 
capsules containing about a dozen eggs, so that infection of the insect 
host is likely to be multiple. The double-pored tapeworm is relatively 
uncommon in man and most of the cases recorded, of which there have been 
less than 100 all told, three in the United States, are among young 
children. Children are more likely than adult human beings to swallow 
fleas, which would explain the greater frequency of infestation among 
children. Another possible explanation of the more common occurrence 
of this parasite among children than among adults is that older persons 
may possess a greater immunity to infection. Prophylaxis against the, 
double-pored tapeworm consists chiefly in keeping dogs and cats free from 
lice and fleas, and so far as human beings are concerned excluding dogs 
and cats, especially if they are lousy or infested with fleas, from human 
habitations. 

Hymenolepis diminuta (Rudolphi, 1819) Blanchard, 1891 

Hymenolepis diminuta (the yellow-spotted tapeworm) is of frequent 
occurrence in the small intestine of rats and mice, particularly the former, 
and of occasional occurrence in the intestine of man. The adaptability 
of the adult tapeworm to hosts so widely different as rodents and human 
beings is paralleled by the adaptability of the larval stage to various 
intermediate hosts. Cysticercoids belonging to this species have been 
recorded in various insects, a Lepidopteron, Asopia farinalis, in both 
larva and imago; a Dermapteron, Anisolabis annulipes; Coleoptera, Akis 
spmosa, Scaurus striatus, and Tenebrio molitor; and fleas Ceratophyllus 
fasciatus, Xenopsylla cheopis, Pulex irritans, and Ctenocephalus cams; 
also in myriapods, Font aria virginiensis and Julus sp. Nicoll and 
Minchin (1911) found the cysticercoids in about 4 per cent of the rat 
fleas (8 out of 207) they examined during a period of thirteen months, 
and they succeeded in infecting rats with the tapeworm by feeding them 
fleas, as Grassi and Rovelli (1892) had previously done by feeding other 
insects. Joyeux (1916) infected the larvae of Asopia farinalis by feeding 
the eggs of H. diminuta and believes the cysticercoids recorded in the 



RELATION OF INSECTS TO THE PARASITIC WORMS 55 

adult moth by Grassi and Rovelli were carried over from the larval stage 
of the insect. He failed in his attempts to infect Forficula auricularia, 
Blatta orientalis, and Blattella germanica. He also failed to infect 
beetles belonging to the species Blaps mortisaga, but succeeded easily in 
infecting the adults of Tenebrio molitor. The larvae of this latter beetle 
according to Joyeux are incapable of acting as intermediate hosts of 
H. diminuta. He was able to infect the larvae of rat fleas and of Pulex 
irritans and Ctenocephalus cams. In these insects the embryos of H. 
diminuta begin immediately to develop into cysticercoids and do not wait 
for the transformation of the larval fleas into adults, as Joyeux found in 
the case of Dipylidium caninum, the embryos of which apparently lie 
dormant in the insect until after it transforms into the adult stage. In 
this country Nickerson (1911) has reared the cysticercoid in myriapods, 
Font aria rirginiensis and Julus sp., fed on the eggs of the tapeworm. He 
failed in his attempts to infect meal worms. 

It is evident that infection of the definitive host with H. diminuta 
results from swallowing infested insects, the latter having become infested 
as a result of swallowing the eggs contained in the feces of animals harbor- 
ing the tapeworms. As a parasite of man in the United States, so far as 
available statistics show, H. diminuta ranks about third in frequency 
among the tapeworms, the beef tapeworm (Tcenia saginata) being the 
most common, and the dwarf tapeworm (H. nana) being next. Evident 
prophylactic measures are those directed toward the destruction of rats 
and mice and the avoidance of the ingestion by human beings of the 
various insects that may serve as intermediate hosts, especially the pro- 
tection of farinaceous foods from insect infestation. 



Hymenolepis nana (Siebold, 1852) Blanchard, 1891 

Hymenolepis nana (the dwarf tapeworm) is a very common intestinal 
parasite of rats and mice and is of rather frequent occurrence in man, 
especially in children. In the United States it ranks second to the beef 
tapeworm in the order of frequency among the tapeworms of man. Its 
life history has not been fully worked out. Grassi (1887), however, has 
found that cysticercoids develop in the intestinal villi of rats that have 
been fed the eggs of the dwarf tapeworm. According to his view the 
cysticercoids later break out of the villi into the lumen of the intes- 
tine and grow into mature tapeworms. The rat thus acts both as inter- 
mediate and definitive host of the dwarf tapeworm, the parasite being 
spread from one rat to another through the medium of the eggs passed 
in the feces. The dwarf tapeworm, according to Grassi's version of the 
life cycle, is an exception to the rule among tapeworms that the adult 
stage occurs in one species of animal and the larval stage in another 



56 SANITARY ENTOMOLOGY 

species likely to be eaten by animals of the species that harbors the 
adult tapeworm. 

Inasmuch as Nicoll and Minchin (1911) have found cysticercoids in 
a rat flea (Ceratophyllus fasciatus) that in details of head structure are 
apparently exactly similar to and specifically identical with the dwarf 
tapeworm, the question arises whether such insects may not act as inter- 
mediate hosts, and whether in addition to the life cycle of an exceptional 
type described by Grassi, the dwarf tapeworm also has a life cycle of 
the ordinary type. T. H. Johnston has found cysticercoids similar to 
those recorded by Nicoll and Minchin in another species of rat flea 
(Xenopsylla cheopis) as well as in Ceratophyllus fasciatus. 

Joyeux (1916) has failed in experiments with fleas belonging to the 
species named and to related species, to infect them with H. nana. He 
states he used both larval and adult fleas. On the other hand he was able 
to confirm Grassi's results and succeeded in infecting a large number of 
rats and mice by feeding them the eggs of the tapeworm. The experi- 
mental evidence thus far available accordingly favors the view that insects 
do not play a necessary part in the life history of the dwarf tapeworm. 
Furthermore, considering the frequency of occurrence of H. nana as 
a parasite of man, and the enormous numbers of the parasites sometimes 
present, it would seem that infection is more likely to occur in the manner 
described by Grassi than as a result of swallowing rat fleas, there being 
of course a greater likelihood of human beings swallowing rat feces or 
fecal matter from other human beings containing large numbers of eggs 
of the tapeworm than of swallowing rat fleas containing a sufficient num- 
ber of cysticercoids to develop into the large number of tapeworms that 
have been found in some cases. 

Choanotoenia infundibulum (Bloch, 1779) Cohn, 1899 

Choanotoenia infundibulum is a common tapeworm of chickens in 
various parts of the world. Grassi and Rovelli (1892) in Italy found 
cysticercoids in the common house fly (Muse a domestica) which on 
account of their morphological similarity to Choanotoenia infundibulum 
they inferred belonged to this species. From the results of experiments 
conducted in this country by Guberlet (1916) it appears safe to conclude 
that the common house fly acts as the intermediate host of the tapeworm, 
Choanotoenia infundibulum, infection of the fly apparently occurring as 
a result of swallowing the eggs of the tapeworm, and the chicken in turn 
acquiring the parasite as a result of swallowing flies infested with the 
cysticercoid stage. Whether infection of the fly regularly occurs during 
the larval or during the adult stage, or during both stages, has not been 
definitely settled. 



RELATION OF INSECTS TO THE PARASITIC WORMS 57 

Prophylaxis in the case of this tapeworm is obviously largely 
dependent upon fly control measures. 

Other Tapeworms 

According to Villot (1883) the larval tapeworm observed by Stein 
(1852) in the larva of Tenebrio molitor belongs to the tapeworm of the 
mouse, known as Hymenolepis microstoma. The same writer (1878, 
1883) also associates with certain tapeworms of shrews, two species of 
larval tapeworms which he found in myriapods, Glomeris limbata. Fur- 
ther investigations of these parasites appear necessary to substantiate 
the views held by Villot as to their specific identity. Ackert (1918, 1919) 
has recently recorded some experiments in which chickens were given 
house flies and became infested with tapeworms (Davainea cesticillus and 
D. tetragona). The immature stages of these parasites were not, how- 
ever, seen in the flies and the possibility is not excluded that the chickens 
became infected from some source other than the flies, notwithstanding 
the precautions taken against extraneous infection. Guberlet (1919) 
caught stable flies (Stomoxys calcitrans) in poultry yards where the 
chickens were commonly infested with Hymenolepis carioca (Magalhaes, 
1898) and fed them to young chicks with the result that some of them 
became infested with this tapeworm. He concludes that the stable fly 
possibly serves as an intermediate host of this tapeworm. 

TREMATODA OR FLUKES 

All species of flukes whose life history is known depend upon molluscs 
as hosts for certain larval stages, and they may or may not require one 
or more additional intermediate hosts before they reach the definitive host. 
It is as intermediate hosts following the first intermediate host, a mollusc, 
that insects can play a part in the propagation of flukes. As yet it has 
not been shown that insects are concerned in the life history of any of 
the flukes (about 100 known species) that affect human beings or domestic 
animals, but as the life history of all of these parasites has not been 
determined it is quite likely that in the case of some species insects will be 
found to act as intermediate hosts. Different species and groups of 
species show various types of life history with reference to the number 
of larval stages through which the parasite passes and the number of 
intermediate hosts required. A comparatively simple life cycle is as 
follows : The mature fluke in the definitive host produces eggs which pass 
to the exterior in the feces. Under suitable conditions of moisture and 
temperature the egg hatches and a ciliated larva, the miracidium, issues. 
If this jniraeidiiun finds a suitable mollusc (different species of molluscs 



58 SANITARY ENTOMOLOGY 

attract different species of miracidia) it burrows into the soft tissues of 
the mollusc and reaching the respiratory chamber proceeds to develop 
into the next stage, the sporocyst. Within the sporocyst by a process 
of internal budding more or less numerous so-called redice develop. The 
redise finally leave the sporocyst and migrate into the liver of the mollusc. 
In the redia several generations of daughter rediae may develop by 
budding. The next stage, developed also by internal budding from the 
redia, is the cercaria. The cercaria of some species is provided with a 
tail by means of which it swims about in the water when it finally escapes 
from the mollusc. The cercaria may be swallowed by or actively pene- 
trate into some animal and become encysted in this animal. Finally when 
the animal harboring encysted immature flukes is swallowed by an animal 
which can serve as a host of the adult fluke, the young flukes thus reach- 
ing their definitive host develop to maturity and the life cycle is complete. 
Following is given a partial list of the insects in which young flukes 
have been recorded. The species to which the young flukes in question 
have been assigned and the final host animals are also indicated. Further 
investigations are likely to show that some of the flukes from insects 
have been misidentified and do not belong to the species to which they 
have been supposed to belong, and the data given in the list should 
not be accepted as fully proved in any case, though there can be no doubt 
in some of the cases cited. No distinction has been made between certain 
and doubtful cases, except that a few that are doubtful are indicated by 
question marks. The determination of species of young flukes found in 
insects has generally been made solely upon their morphological similarity 
to adults occurring in vertebrate hosts and it is quite likely that mistakes 
have been made by investigators of these parasites just as mistakes have 
frequently been made in the association of immature and adult parasites 
belonging to other groups of worms. 



NEMATODA OR ROUNDWORMS 

Among parasitic worms the species of nematodes are more numerous 
than either the species of tapeworms or flukes. Nematodes as a group 
are not exclusively parasitic and thousands of free-living species are 
known to exist, although comparatively few have been described. Many 
species of nematodes are parasites of insects only and do not occur in 
other animals. Insects therefore harbor parasitic nematodes which belong 
to them exclusively as well as the larval stages of nematodes that occur 
in higher animals in their adult stage. The ubiquity of free-living nema- 
todes introduces a frequently troublesome complication into the study 
of the life histories of monoxenous parasitic nematodes of which there 
are many species, and the common occurrence of parasitic nematodes 



RELATION OF INSECTS TO THE LIFE CYCLE OF FLUKES 



Insect Host 


Adult Fluke, 


Final Host 


Coleoptera 






Ilybius fuliginosus (Fabricius) (adult) 


Haplometra cylindracea 


Fiogs 


Water beetle (larva) 


Prosotocus confusus 


" 


<< « << 


Pleurogenes medians 


" 


<< it « 


claviger 


a 


Lepidoptera 






Nymphula nymphaeata (Linnaeus) (larval 


Unknown 


Unknown 


Diptera 






Anopheles maculipennis Meigen (claviger Fa- 






bricius) (adult) 


« 


(C 


Anopheles rossi Giles (adult) 


<« 


<< 


Chironomus plumosus Linnaeus (larva) 


Lecithodendrium ascidia 


Bats 


Culex quinquefasciatus Say (fatigans Wiede- 






mann) (adult) 


Unknown 


Unknown 



Trichoptera 

Anabolia nervosa (Leach) Curtis 

Anabolia nervosa (larva) 
Chaetopteryx villosa (Fabricius) (larva) 

Drusus trifidus McLachlan (larva) 

Limnophilus rhombicus (Linnaeus) (larva) 
griseus (Linnaeus) (larva) 
lunatus (Curtis) (larva) 
flavicornis (Fabricius) (larva) 

Mystacides nigra (Linnaeus) (larva) 

Notidobia ciliaris (Linnaeus) (larva) 

Phryganea sp. 

Phryganea grandis (larva) 

Rhyacophila nubila Zetterstedt (larva) 

Neuroptera 
Sialis lutaria (Linnaeus) (larva) 

Odonata 
JSschna (larva and adult) 
Agrion (larva) 



Calopteryx virgo (Linnaeus) 

" (larva and adult) 
Cordulia (larva) 
Epitheca " 



Plectoptera 

Cloeon dipterum (Linnaeus) Stephens (larva) 
Ephemera vulgata Linnaeus (larva) 



Ephemeridae (laiva) 

Plecoptera 

Perlidae (larva) 



Allocreadium isoporum 

Opisthioglyphe rastellus 
Allocreadium isoporum 

Unknown 
Opisthioglyphe rastellus 



Unknown 

Lecithodendrium chilostomum 
Unknown 



Prosotocus confusus 
Gorgodera pagenstecheri 

varsoviensis 
Pleurogenes medians 
Halipegus ovocaudatus 
Pneumonceces similis 
Prosotocus confusus 
Gorgodera cygnoides 

pagenstecheri 
varsoviensis 



? Opisthioglyphe rastellus 
Allocreadium isoporum 

? Opisthioglyphe rastellus 
Lecithodendrium ascidia 



Lecithodendrium ascidia 
Unknown 



Cyprinoid 
fishes 

Frogs 

Cyprinoid 
fishes 

Unknown 

Frogs 



Unknown 

Bats 

Unknown 
Bats 



Unknown 



Frogs 



Cyprinoid 

fishes 
Frogs 
Bats 



Unknown 



59 



60 SANITARY ENTOMOLOGY 

among insects introduces an equally troublesome complication into the 
study of the life histories of the heteroxenous nematodes parasitic in 
higher animals, for which insects may serve as intermediate hosts. About 
250 species of nematodes have been recorded as parasites of man and 
domestic animals. Many of these require no intermediate hosts, but 
some are heteroxenous parasites, and a number of these are known to have 
intermediate stages in insects and closely related arthropods. In the 
following discussion, in addition to the nematodes parasitic in man and 
domestic animals, certain species parasitic in other animals are also con- 
sidered because of the part played by insects in their life history. For 
convenience they may be placed in two groups, (1) those in which the 
eggs or first-stage larvae leave the body of the final host in the feces, and 
(2) those in which the first-stage larva? occur in the blood or lymph of 
the final host and leave the body through ingestion by bloodsucking 
insects. 

1. Parasitic Nematodes Whose Eggs or Larva? Leave the Body of •the 

Final Host in the Feces 

Protospirura muris (Gmelin, 1790) Seurat, 1915 

This nematode, parasitic in its adult stage in the stomach of various 
species of rats and mice, is of special interest historically as being the 
first parasite in whose transmission to its final host an insect was found 
to be concerned. Stein in 1852 recorded the presence of encysted nema- 
todes in the larvae of meal beetles (Tenebrio molitor). Leuckart (1867) 
and Marchi (1867) fed eggs of Protospirura muris (Spiroptera obtusa) 
to meal beetle larvae and followed the development of the young nematodes 
up to the encysted stage found by Stein. This development is completed 
in about six weeks after ingestion of the eggs. The development to the 
adult stage was also followed in mice fed with the encysted nematodes from 
meal worms. Johnston (1913) has recorded encysted nematode larvae 
which appeared to him identical with those of P. muris in the body cavity 
of a rat flea (Xenopsylla cheopis). 

Spirocerca sangumolenta (Rudolphi, 1819) Railliet & Henry, 1911 

The adults of this nematode live in tumors of the stomach and 
esophagus of the dog and the wolf. The eggs unhatched pass out of the 
body of the dog in the feces. Grassi (1888) found encysted iarval nem- 
atodes in cockroaches (Blatta orient alis) which he suspected were the 
larvae of S. sanguinolenta. Dogs fed with these encysted nematodes after 
five days showed the larvae free in the stomach ; after ten days the young 
worms were further developed and were firmly attached to the mucosa 



RELATION OF INSECTS TO THE PARASITIC WORMS 61 

of the esophagus ; and after fifteen days they had sunk themselves into 
the wall of the esophagus and had developed still further. Grassi con- 
cluded that cockroaches act as intermediate hosts, swallowing the eggs in 
the feces of infested dogs, and'in turn being swallowed by dogs. Seurat 
(1913), however, believes that Grassi was mistaken as to the identity of 
the encysted nematodes found in the cockroaches, and that they were 
really the larvae of Spirura gastrophila, the adult of which occurs in the 
stomach of the cat, hedgehog (Erinaceus algirus), and fox (Vulpes vulpes 
atlantica). Seurat (1912, 1916) finds what he considers to be the larvae 
of S. sanguinolenta encysted in a great variety of animals including 
beetles, reptiles, birds, and mammals. The presence of the encapsulated 
larvae in various vertebrates he explains as the result of the ingestion of 
insects infested with the larvae. If the vertebrate is not a host in 
which the parasites can continue their development as they would in 
their normal host the dog, they migrate into the wall of the alimentary 
tract or mesentery and become reencysted without further development. 
If, however, the infested insect is swallowed by a dog the larvae, after 
they have been freed by digestion of the cysts surrounding them, continue 
their development and finally reach maturity. Seurat in fact found 
that encysted larvae in insects identified as those of S. sanguinolenta when 
fed to mice became reencysted in the manner described. Seurat (1916) 
records the following insects as hosts of the larvae of S. sanguinolenta, all 
of them beetles: Scarabaus (Ateuchus) sacer, vScarabams (Ateuchetus) 
variolosus, Akis goryi, Geotrupes douei, Copris hispanus, and Gymno- 
pleurus sturmi. According to Seurat the life cycle of S. sanguinolenta 
would be as follows : The eggs pass out of .nfested dogs in the feces, 
are ingested by beetles, hatch, and the larvae after a period of growth and 
development become encysted. If infested insects are swallowed by dogs 
or wolves the larval worms are released from their capsules and develop to 
maturity. If the insects are swallowed by other animals, the larvae may 
become freed from their cysts as in the alimentary tract of the dog, 
but the}- are unable to develop further and leave the lumen of the 
alimentary tract and become reencysted in the tissues to which they 
migrate. In such a case, of course, there is a possibility of their resuming 
their development if the infested animal should afterwards be devoured by 
a dog or a wolf, but this possibility apparently has not yet been sub- 
stantiated. 

Spirura gastrophila (Mueller, 1894) Marotel, 1912 

This nematode in the adult stage occurs in the stomach and the lower 
end of the esophagus of the cat. It has also been recorded by Seurat 
(1913) from the stomach of a hedgehog (Erinaceus algirus) and the 
stomach and esophagus of a fox (Vulpes vulpes atlantica), and by the 



62 SANITARY ENTOMOLOGY 

same author (1918) in the esophagus of the mongoose (Herpestes 
ichneumon). This author identifies certain encysted larval nematodes 
found in a species of Onthophagus, in Blatta orientalis, in Blaps strauchi, 
and in Blaps sp. (near appendiculata) as belonging to S. gastrophila. 
He thinks the parasites found in the cockroach and called Filaria ryti- 
pleurites by Deslongchamps (1824), and those identified as such by Galeb 
(1878) who associated them with an insufficiently described adult 
nematode of the rat, are probably the same as those he identified as the 
larvae of S. gastrophila. He also dismisses Grassi's experiments as insuffi- 
cient to show that the nematodes encysted in cockroaches are the larvae 
of Spirocerca sanguinolenta as Grassi believed, and concludes that Grassi 
was mistaken and was really dealing with the larvae of Spirura gastrophila. 
Seurat (1919) adds Akis goryi to the list of insect hosts of the larvae of 
S. gastrophila. 

Gongylonema scutatum (Mueller, 1869) Railliet, 1892 

This nematode in the adult stage is a common parasite in the mucous 
membrane of the esophagus of cattle, sheep, and other ruminants, and 
has also been recorded from the horse. Ransom and Hall (1915, 1916, 
1917) have shown that various species of dung beetles (Aphodius 
femoralis, A. granarius, A. fimetariws, A. coloradensis, A. vittatus, 
Onthophagus hecate, and 0. pennsylv aniens ) act as intermediate hosts. 
Experimentally, cockroaches (Blattella germanica) can also be made to 
serve as intermediate hosts, a part of course which they do not play 
under natural conditions. The eggs of the parasite pass out of the body 
of the definitive host in the feces and are swallowed by dung beetles. They 
hatch in these insects, and the larvae entering the body cavity undergo a 
certain growth and development, reaching their infective stage in about 
a month, meanwhile becoming enveloped in capsules in which they lie in 
a coiled-up position. Further development waits upon the swallowing of 
the infested insect by a cow, sheep, or other suitable host as may readily 
occur while the animal is grazing, the insect being ingested with the herb- 
age upon which it happens to be. Following their ingestion by the defini- 
tive host, the larvae are released from their capsules and develop to matur- 
ity. Seurat (1916) has described some larval nematodes from the abdom- 
inal cavity of Blaps strauchi, Blaps appendiculata, and Blaps sp. (near 
appendiculata ) in Algeria that he identifies as Gongylonema scutatum. 
As pointed out by Ransom and Hall (1917), however, these evidently 
belong to another species as they do not correspond to the forms shown 
by these writers to be the larvae of G. scutatum. Seurat (1919) adds 
Blaps emondi to the list of insects in which he has found the larvae 
in question. 



RELATION OF INSECTS TO THE PARASITIC WORMS 63 

Gongylonema mucronatum Seurat, 1916 

This nematode occurs in the adult stage in the mucosa of the esophagus 
of the Algerian hedgehog (Erinaceus algirus). According to Seurat 
(1916) its larval stage is found encapsuled in the body cavity of various 
species of coprophagous beetles, Ateuchus sacer, Chironitis irroratus, 
Onthophagus bedeli, Gymnopleurus mopsus, Gymnopleurus sturmi, and 
Geoi rapes douei, but there appears to have been some confusion as to 
the identity of the larvae in question, and further investigation of the life 
history of this species is desirable (Ransom and Hall, 1917). 

Gongylonema brevispiculum Seurat, 1914 

Seurat (1916), in addition to forms found in different species of Blaps 
that he considers to be third stage larvae of Gongylonema scutatum, has 
described as second stage larvae of G. scutatum some larval nematodes 
found encysted in the abdominal cavity of Blaps sp. and Blaps strauchi 
in certain localities in Algeria. In a later paper, however (1919), he 
has expressed the opinion, based upon the morphology of the worms and 
a knowledge of the mammalian fauna in the region in which the parasites 
are found, that these larvae are third stage larvae and belong to the species 
G. brevispiculum the adult of which occurs parasitic in the cardiac portion 
of the stomach of a species of jerboa (Dipodillus campestris). 

Further investigation seems desirable as to the identity of the supposed 
larvae of Gongylonema brevispiculum as well as of the other larvae of 
Gongylonema that have been assigned to various species on a basis of 
apparent morphological similarities and general considerations. A con- 
tinuation of the excellent work already done by Seurat relating to the 
larval forms of Gongylonema will no doubt clear up the confusion that 
now exists. 



Gongylonema neoplasticum (Fibiger and Ditlevsen, 1914) Ransom and 

Hall, 1916 

This nematode occurs in the adult stage in the mucosa of the stomach, 
esophagus and mouth of the rat. It has been reared experimentally 
in the rabbit and guinea pig as well as in the rat and mouse. It is of 
special interest from the medical standpoint because it is commonly 
associated with and perhaps stands in etiological relationship to gastric 
carcinoma of rats. Fibiger and Ditlevsen (1914) have proved that cock- 
roaches (Periplaneta americana, Blatta orientalis, and Blattella german- 
ica), and a grain beetle (Tenebrio molitor) can act as intermediate hosts. 
The eggs are passed in the feces of infested rats and if ingested by one 



64 SANITARY ENTOMOLOGY 

of the insects named will hatch, the larvae within twenty days after 
ingestion of the eggs developing to the infective stage. In this stage the 
larvae are coiled up in cysts in the muscles of the prothorax and legs, 
differing in location from the larvae of G. scutatum which in artificially 
infected cockroaches, as in their normal hosts, dung beetles, are found 
encysted in the body cavity. 

Arduenna strongylina (Rudolphi, 1819) Railliet and Henry, 1911 

This nematode in its adult stage occurs in the stomach of the pig. 
Seurat (1916) has recorded the presence of larval nematodes in the 
stomach of a pig associated with adults of A. strongylina which he con- 
siders belong to this species. He has found morphologically similar larval 
nematodes encapsuled in the body cavity of Aphodius rufus castaneus and 
states that they also occur in beetles of the genus Onthophagus* Ap- 
parently no feeding experiments have been carried out. Presumably the 
life history would be similar to that of Gongylonema scutativm, Proto- 
spirura muris, etc., that is, the eggs of the parasite passed in the feces are 
swallowed by beetles, the larvae develop in these insects to the infective 
stage, and are transferred to the definitive host when the beetles are 
swallowed by a pig, after which the young worms complete their develop- 
ment to maturity. Seurat (1919) records the presence of encysted larvae 
of A. strongylina in the stomach wall of the Algerian hedgehog (Erinaceus 
algirus). Apparently, therefore, the larvae of this species that occur 
encysted in insects, like those of Physocephalus sexalatus and Spirocerca 
sanguinolenta, if ingested by vertebrates other than the normal hosts of 
the adult worms, migrate out of the lumen of the digestive tract and 
become reencysted in the neighboring tissues. 

Physocephalus sexalatus (Molin, 1860) Diesing, 1861 

The adults of this nematode live in the stomach of the pig, dromedary, 
and donkey. Seurat (1913) has found two successive larval stages pre- 
ceding the adult in the stomach of the definitive host (donkey) and has 
also (1916) established the common occurrence of the earlier of these two 
stages in various dung beetles (Scarabams [Ateuchus] sacer, S. 
[Ateuchetus] variolosus, Geotrupes doue% Onthophagus nebulosus and 
0. bedeli). Pigs of course are commonly known to be coprophagus in 
their feeding habits and Seurat states that the donkeys of Algeria, where 
his investigations were made, commonly devour fecal matter swarming 
with dung beetles. The way in which the larvae of P. sexalatus reach their 
final host is therefore evidently through the ingestion of infested beetles 
by pigs, donkeys, or dromedaries. Presumably of course the beetles be- 



RELATION OF INSECTS TO THE PARASITIC WORMS 65 

come infested by eating the eggs of the parasite which are passed in the 
feces of infested pigs, donkeys, and dromedaries. As in the case of 
Spirocerca sanguinolenta Seurat finds encysted larvae of P. sexalatus in 
various vertebrates in Algeria, particularly reptiles and insectivores. 
Their presence in these animals he would explain in the same way as he 
explains the presence of the encysted larvae of S. sanguinolenta in such 
animals, that is, the larvae present in insects devoured by the animals in 
question are unable to continue their development as they would in pigs 
and other suitable hosts. On the other hand they do not succumb in their 
strange environment nor do they pass through the alimentary tract with 
the feces but penetrate into the walls of the stomach and into other tissues 
and become reencysted, surviving in this condition more or less indefinitely. 
They may thus be considered parasites that have gone astray but still 
capable of existence in their abnormal environment. The possibility of 
their developing to maturity after reencystment in a strange host if this 
animal should be eaten by a pig has not been substantiated experimentally. 
Seurat (1916) has counted 4,880 larvae identified as P. sexalatus in a 
single beetle, Scarabtfus (Ateuchus) sacer. In addition there were 68 
larvae of Spirocerca sanguinolenta in the same beetle, making a total of 
4,948 larvae in the one insect. 

Habronema muscm (Carter, 1861) Diesing, 1861 

This nematode in the adult stage occurs in the stomach of horses and 
other equines, commonly in association with another closely related 
species, H. microstoma. The life history of H. musca? has been shown to 
be as follows (Ransom, 1911, 1913; Hill, 1918; Bull, 1919) : The eggs 
or the larvae pass out of the body of the host in the feces. They enter 
the bodies of the larvae of the common house fly, probably being swallowed, 
though the mode of entrance has not been determined by direct observa- 
tion. The worm larvae grow and develop in the developing flies and at 
about the time the adult insects emerge from the pupal stage the larvae 
reach the infective stage. In this stage they are most commonly found 
in the proboscis. The ingestion by horses of flies harboring the larvae 
brings the young parasites into the location where the adult occurs, 
and presumably this is the common method by which the larvae reach their 
final host. The frequent swallowing of flies by horses is an undoubted 
fact. The mouths of horses are very attractive to house flies especially 
while the horses are eating, as any one can determine by a few minutes' 
observation of the animals during the fly season. There is also another 
possible and very probable way in which the larvae are transferred to 
horses, suggested of course by the habit of the larvae of congregating 
in the proboscis of the fty. We may expect that it will be demonstrated 



66 SANITARY ENTOMOLOGY 

in analogy with what has been shown to occur in Filaria transmission by 
mosquitoes, that the larvae of H. muscce can actively leave the proboscis 
of the fly while the insect is sucking moisture from the mouth or lips of 
the horse. There is ' already indirect evidence that this does occur. 
The researches of Descazeaux (1915), Bull (1916), and Van Saceghem 
(1917) have shown that the nematodes which occur in cutaneous granulo- 
mata and so-called summer sores of horses are morphologically similar 
to the larvae of Habronema muscce and in all probability*belong to this 
or a closely related species. Recently Van Saceghem (1918) from investi- 
gations carried out in Africa has reached the conclusion that the 
nematode of summer sores is Habronema muscat and that it is introduced 
by flies. Larvae from infested flies were placed in the eye of a horse kept 
in an insect-proof enclosure, with the result that conjunctivitis and 
verminous nodules of the nictitating membrane developed. In another 
experiment two wounds were made on the skin of a horse, one protected 
against flies and the other left uncovered. The horse was placed in a 
stable in which 20 per cent of the flies were infested with Habronema. 
The unprotected wound became transformed into a typical summer sore. 
Bull (1919), who has made an extended study of cutaneous granulomata 
of horses in Australia, believes that the larvae of Habronema megastoma 
are more often responsible for the production of habronemic granulomata 
than either H . muscce or H. microstoma. 

Whether the Habronema larvae in summer sores are able to migrate 
ultimately to the stomach and complete their development to maturity 
remains to be determined. Bull (1919) thinks it unlikely that the larvae 
of Habronema are able to reach the alimentary canal from the submucosa 
of the external mucous membranes or from the subcutaneous tissues, and 
Hill (1918) also notes that the evidence of the occurrence of such a 
migration is quite insufficient. 

It is of interest to note that Habronema muscaz was known as a 
parasite of the fly long before its relation to the horse was demonstrated. 
Carter in 1861 was the first to record the presence of the nematodes in 
flies, following which they were frequently observed by entomologists and 
others who had occasion to examine the proboscis of the fly under the 
microscope. 

Larval nematodes very similar to H. muscce have been seen in the 
proboscis of Stomoxys calcitrans by Johnston and others. The researches 
of Hill (1918) and Bull (1919) have shown that as far as their experience 
has gone the larvae in this species of fly have invariably been Habronema 
microstoma so that the occurrence of H. musca in S. calcitrans appears 
questionable. 

The fact that these more or less injurious parasites of the horse 
depend upon flies for their existence is a point which may be added to 



RELATION OF INSECTS TO THE PARASITIC WORMS 67 

those commonly used in arguments for the necessity of fly eradication. 
The possibility is also not excluded that flies may introduce Habronema 
larvae into human beings, in whose tissues they may perhaps Le able to live 
for a time and do considerable damage. Though there is no evidence 
that this ever occurs, the possibility is one that deserves consideration 
from those who have opportunity to investigate the relation of flies to 
wounds and other lesions of the skin and mucous membranes. 

Habronema microstoma (Schneider, 1866) Ransom, 1911 

Hill (1918) and Bull (1919) have shown that Habronema microstoma, 
which, like H. musca?, occurs in the adult stage in the stomach of the 
horse and other equines, has a life history similar to that of H. muscat. 
Both of these writers have occasionally observed the presence of H. 
microstoma in Musca domestica under experimental conditions but find 
that the usual intermediate host is Stomoocys calcitrans. As they 
repeatedly failed to infect S. calcitrans with the larvae of H. musca? it is 
probable that the forms from S. calcitrans reported by Johnston (1912) 
and others as H. musca? were H. microstoma. Bull (1919) is of the 
opinion that the larvae of H. microstoma may sometimes be concerned in 
the production of cutaneous granulomata of horses and that presumably 
they are introduced into the skin by the proboscis of an infested fly. 

Habronema megastoma (Rudolphi, 1819) Seurat, 1914 

Habronema megastoma in its adult stage occurs in tumors in the 
stomach of horses and other equines. Hill (1918) and Bull (1919) have 
found that its life history is similar to that of H. musca?, the house fly 
(Musca domestica) acting as intermediate host in both cases. Attempts 
to infect Stomoxys calcitrans with this species failed. Bull (1919) be- 
lieves that the larvae of H. megastoma introduced by infested flies are 
the usual cause of habronemic granuloma of horses. So far as the normal 
life history of H. megastoma is concerned he thinks that the presence of 
the larvae in the skin or mucous membranes of horses is to be considered 
accidental and that it is unlikely that they can reach the alimentary tract 
from such locations and become mature. According to his view, there- 
fore, which is shared by Hill (1918), H. megastoma and also the other 
species of Habronema reach the stomach of the horse as a result of the 
animal's swallowing infested flies. 

Acuaria spiralis (Molin, 1858) Railliet, Henry and Sisoff, 1912 

The adults of this nematode have been recorded as parasitic in the 
esophagus and stomach of the domestic fowl. Insects have not been 



68 SANITARY ENTOMOLOGY 

shown to act as intermediate hosts, but insect-like animals commonly 
known as sow-bugs apparently act as intermediate hosts, Piana (1897) 
having found larval nematodes in an isopod (Porcellio Icevis) that corre- 
sponded in morphology with immature nematodes found in chickens 
harboring also the adult worms. Furthermore these larval nematodes 
occurred in sow-bugs only in the locality where the chickens were found 
to be infested. Although Piana identified the parasites that he found in 
chickens as Dispharagus nasutus (Rudolphi), it is apparent from his 
description and figures that they belonged to the species Acuaria spiralis 
(Molin). 

Filaria gallimarwm Theiler, 1919 

Theiler (1919) has recorded the occurrence of larval nematodes in a 
species of termite (Hodotermes pretoriensis). Among the termites only 
the workers were found to harbor these parasites, no infested soldiers 
having been discovered. Infested termites can easily be distinguished 
by the swollen abdomen which gives the insect a sort of balloon-like 
appearance. According to Theiler, on many South African farms the 
custom exists of digging up nests of termites and allowing the chickens 
to feed on the insects, and the droppings of chickens running in the fields 
are naturally scattered about and serve as food for the termites. Infested 
termites were fed to young chickens that had been hatched in an incubator. 
Adult worms that had evidently developed from the larvae parasitic in 
the termites were found in the intestine or stomach in 15 out of 16 
chickens that had been thus fed, but none were found in control chickens. 
The proper generic position of this nematode described by Theiler as a 
Filaria remains to be determined. 

Ascaris lumbricoides Linnaeus, 1758 

This common parasite of man has been definitely shown to have a 
direct life history without intermediate host. The opinion of Linstow 
(1886) that a species of Julus (guttulatus) acts as the intermediate host 
is without foundation. The common house fly may swallow eggs of this 
parasit? as well as those of various other parasites which occur in the 
feces of infested human beings. The eggs pass through the intestine of 
the fly unhatched. Flies may thus scatter the eggs of Ascaris but there 
is no evidence that mechanical carriage of the eggs in this way assists 
materially in the spread of the parasite. There are various other natural 
agencies more effective than insects in spreading infection with parasites 
such as Ascaris. Stiles, however (according to Nuttall, 1899), fed 
females of Ascaris lumbricoides containing eggs to fly larvae (Musca 
domestica) and afterwards found the eggs in later stages of development 



RELATION OF INSECTS TO THE PARASITIC WORMS 69 

in the pupae and adult flies that developed from the larvae. This sug- 
gested the possibility that flies having become infested as larvae might 
convey the parasite to man by falling into or depositing their excreta 
on food. Apparently these experiments have not been repeated. 



2. Parasitic Nematodes Whose First-stage Larvae Occur in the Blood or 

Lymph of the Final Host and Leave the Body Through Ingestion 

by Bloodsucking Insects 

Filaria bancrofti Cobbold, 1877 

This important parasite of man is widely distributed throughout the 
world in tropical and subtropical countries. It occurs in the United 
States, though apparently it is by no means common. Historically it is of 
special interest because of the fact that it is the species which Manson 
(1878) showed passed through certain metamorphoses in the bodies of 
mosquitoes after the larvae had been sucked up by these insects in the 
blood of human beings affected with fllariasis. Manson's researches 
coupled with confirmatory work by other investigators established the 
novel fact of the transmission of an animal parasite by a bloodsucking 
insect, and may be taken as the starting point in the development, of our 
knowledge concerning the part played by such insects in the spread of 
disease-causing organisms. Lewis had also observed the passage of the 
larvae from the human host into mosquitoes. The first observation of 
these larvae in man was recorded by Demarquay in 1864 in Paris, the adult 
female was discovered by Bancroft in 1876 in Queensland, and the adult 
male by Bourne in 1888. 

The adults of this species live in the lymphatic system, both vessels 
and glands. The first-stage larvae which are provided with a thin cutic- 
ular sheath, apparently the transformed egg shell, are found in the blood 
stream, usually periodically as first shown by Manson, that is, in consid- 
erable numbers only at night or rather during the hours of sleep, as the 
periodicity may be reversed by making the patient sleep during the day 
time. One of the names of the parasite, Filaria noctuma, is based upon 
the periodicity of the appearance of the larvae in the blood. Various 
pathological conditions have been attributed to Filaria bancrofti such as 
adenitis, lymphangitis, abscesses, lymph scrotum, chyluria, and other 
disturbances of the lymphatic system. The connection between fllariasis 
and elephantiasis is still a matter of argument among pathologists. 

When taken into the stomach of a mosquito the larvae lose their cutic- 
ular sheaths. Within 24 hours they leave the alimentary tract, pass 
into the body cavity, then into the muscles of the thorax. In the muscles 
they become shortened to about half their original length and meanwhile 



70 SANITARY ENTOMOLOGY 

increase to twice or more than twice their original thickness, developing 
into what is known as the sausage stage of general occurrence in the 
development of Filaria larvae. Developing beyond this stage they increase 
rapidly in length, cast their skins at least once, and in one to two weeks 
after infection of the mosquito, or longer, according to temperature and 
the species of mosquito infected, they complete their larval development 
so far as the intermediate host is concerned, reaching a length finally 
about three to five times the length of the first-stage larvae and a thickness 
about three or four times the original thickness. They leave the muscles, 
enter the body cavity, and migrate into various locations, posterior por- 
tions of the body, legs, palpi, but in greatest numbers into the labium. 
From the evidence afforded by the experiments of Noe (1900) with 
Dirofilaria immitis and additional experiments by Bancroft (1901), 
Lebredo (1904-1905), Fiilleborn (1908), and others, it has been con- 
cluded by analogy in the case of Filaria bancrofti that when an infected 
mosquito bites a human being the filaria larvae bore through a thin portion 
of the labium known as Dutton's membrane, and more rarely other thin 
portions of the proboscis, actively penetrate the skin of the individual 
attacked, and reach the lymphatic system where they complete their 
development to maturity. 

Both anopheline and culicine mosquitoes can serve as intermediate 
hosts of Filaria bancrofti including the following species (see also 
Chapter XVII) : 

Anopheline mosquitoes 

Anopheles (Myzomyia) rossi Giles. 

" (Pyretophorus) costalis Loew. 

" (Myzorhynchus) sinensis Wiedemann. 

" " " peditamiatus Leicester. 

" " barbirostris Van der Wulp. 

Culicine mosquitoes 

Culex pipiens Linnaeus Aedes argent eus Poirret (Stego- 

myia calopus Meigen) 
" quinquef asciatus Say (fati- Aedes gracilis Leicester (Stego- 
gans Wiedemann) myia) 

Aedes scutellaris Walker (Culex 
" gelidus Theobald albopictus Skuse) 

" sitiens Wiedemann Mansonioides uniformis Theobald 

Mansonioides annulipes Theobald 
Scutomyia albolineata Theobald 
Taeniorhynchus domesticus Lei- 
cester 



RELATION OF INSECTS TO THE PARASITIC WORMS 71 

Besides those named about a dozen other species of mosquitoes have 
been tested as hosts of Filaria bancrofti with negative results, or with 
results showing that the parasites would only develop imperfectly. Fleas, 
lice, and Stomoxys have been tested with negative results. 

Prophylaxis against Filaria bancrofti evidently consists in measures 
similar to those employed in malaria eradication with reference to mos- 
quito control. 

Filaria (Loa) loa (Cobbold, 1864) 

This parasite of man is a West African species. It has been brought 
to America in the slave trade but never established in the New World. 
The adults live usually in the subcutaneous connective tissue but have 
been found elsewhere in relation with the serous membranes of the ab- 
dominal and thoracic viscera. They move about from place to place 
and can change their location rather rapidly; for example, one of these 
worms has been seen to cross the bridge of the nose beneath the skin 
within a period of an hour or two. In their progress beneath the skin 
in various parts of the body they give rise to transient edematous areas 
known as Calabar swellings. The larvae produced by the females enter 
the blood stream where they are found in the peripheral vessels during 
the day time, contrary to the habits of the larvae of Filaria bancrofti. 
Because of this characteristic periodicity of the larvae, Filaria loa has 
been also named F. diwrna. The larvae of F. loa are provided with a 
sheath relatively much longer than that of the larvae of F. bancrofti. 

Experiments with various anopheline and culicine mosquitoes, and 
Glossina palpalis have given negative results as to the possibility of these 
insects acting as intermediate hosts. From Leiper's (1913) researches, 
it would appear that a species of Chrysops (probably C. dimidiata or 
C. longicornis) acts as the intermediate host of Filaria loa, the larvae 
undergoing their development in the salivary glands of the insect. Ac- 
cording to Ringenbach and Guyomarc'h (1914), the intermediate host in 
the Congo is Chrysops centwrionis. Kleine (1915) in West Africa found 
32 out of 600 Chrysops examined, to be infested with larval nematodes 
which he took to be the larvae of F. loa though he does not give sufficient 
evidence to support his claims. 

Filaria demarquayi Manson, 1895 

This parasite, generally considered identical with Filaria juncea and 
F. ozzardi, occurs in man in the West Indies and in British Guiana. The 
adult has been found in the mesentery and under the peritoneum of the 
abdominal wall. The first-stage larvae occur in the blood stream. Their 
appearance in the circulation is not periodic. According to Low (1902) 



72 SANITARY ENTOMOLOGY 

the larvae can be developed to the so-called "sausage" stage in Aedes 
argenteus (Stegomyia calopus). Experiments with Anopheles albimanus 
(albipes), Culex taeniatus, C. quinquefasciatus (fatigans), and other 
mosquitoes, fleas, and ticks failed to result in any development of the 
larvae. Fiilleborn (1908) was able to develop the larvae to the sausage 
stage in Anopheles maculipennis and Aedes argenteus (Stegomyia calo- 
pus), but no development occurred in the tick, Ornithodoros moubata. 
Further investigations are necessary to determine what insects serve as 
intermediate hosts for F. demarquayi. 

Filaria philippinensis Ashburn and Craig, 1906 

The adult stage of this parasite of man is unknown. The first-stage 
larvae occurring in the blood of man are morphologically identical with 
those of Filaria bancrofti. Unlike the latter, however, they show no 
periodicity. Ashburn and Craig (1907) have shown that the larvae will 
undergo development in mosquitoes, Culex quinquefasciatus (fatigans). 
similar to that of the larvae of F. bancrofti. It is questionable whether 
F. philippinensis should be recognized as a distinct species. 

Filaria tucumana Biglieri and Araoz, 1917 

This species, the adults of which are unknown, is based on microfilarias 
found frequently in the blood of human beings in Argentina. It appears 
to be comparatively harmless. Biglieri and Araoz (1917) conclude that 
mosquitoes act as intermediate hosts and apparently consider Aedes 
argenteus (Stegomyia calopus) the most important vector, though defi- 
nite proof of this has not been, obtained. 

Filaria cy p seli* Armett, Dutton and Elliott, 1901 

The adult stage of Filaria* cypseli occurs in the subcutaneous tissue 
of the head of the swift, Cypselus affinis, also beneath the subcranial 
fascia. The embryos or first-stage larvae occur in the lymph and rarely 
in the peripheral blood of infested birds. Dutton (1905) has described 
various larval stages of the parasite which he finds in an undetermined 
species of bird-louse belonging to the subfamily Leiothinae that occurs 
on swifts. The first-stage larva as it is found in the blood of the bird 
and the stomach of the louse is provided with a sheath as in various 
other species of Filaria. This sheath is lost and the larva probably soon 
penetrates the stomach wall. The next stage of the parasite is found 
in the fat-body of the louse as are two later stages described by Dutton. 
The last stage of development seen by him is found free in the body 



RELATION OF INSECTS TO THE PARASITIC WORMS 73 

cavity and this is probably the stage in which the parasite is trans- 
ferred to the bird; whether as a result of ingestion of the louse by the 
swift, or as a result of the active migration of the worm from the 
louse while the insect is engaged in biting, has not been determined. 

Filaria martis Gmelin, 1790 

Filaria martis (or Filaria quadrispina) according to various writers 
occurs in its adult stage beneath the skin and in the abdominal and 
thoracic cavities of Mustela foina. Baldasseroni (1909) has found filaria 
embryos in the intestine of ticks {Ixodes ricinus) taken from a marten 
harboring the adult nematode, and he suggests that ticks may act as 
intermediate hosts. As in the case of Acanthocheilonema grassii, further 
evidence is necessary before ticks can be considered to play a part in the 
life history of Filaria martis. 

Dirofilaria immitis (Leidy, 1856) Railliet and Henry, 1911 

This nematode, sometimes erroneously listed as a parasite of man, 
lives in the right side of the heart and pulmonary artery of the dog. 
The larvae are found in the circulation, most numerous at night as in 
the case of Filaria bancrofti. As would be expected from the location 
of the adult parasite it may give rise to serious symptoms, and affected 
dogs commonly succumb to the disturbances which it causes. It is a 
troublesome parasite among hunting dogs in the Southern United States. 
Noe (1900) showed that the larvae of this nematode continue their de- 
velopment in certain species of mosquitoes when sucked up with the 
blood of infested dogs. In 24 to 36 hours after reaching the stomach 
of the mosquito the larvae pass into the Malpighian tubules. They 
undergo a certain growth and development in this location, and 11 or 12 
days after reaching the mosquito they break out of the tubules, enter 
the body cavity, and migrate to the labium. From the labium of the 
mosquito they reach their final host, the dog, in the same manner as 
F. bancrofti reaches its human host, namely, by breaking through thin 
portions of the cuticle of the labium at the time the mosquito is engaged 
in biting its victim and then penetrate the skin, finally migrating to the 
heart. Mosquitoes infested with the larvae of D. immitis are commonly 
killed by the parasites owing to their destructive action on the Malpighian 
tubules, Noe having observed that only about half the mosquitoes that 
become, infested survive. In Italy the common intermediate hosts appear 
to be Anopheles maculipennis, A. bifurcatus, A. (Myzorhynchus) sinensis 
pseudopictus, and A. (Myzomyia) superpictus among anophelines ; culi- 
cines, according to Noe such as Culex penicillaris, C. malaria c, and ex- 
ceptionally C. pipiens, can also act as intermediate hosts. 



74 SANITARY ENTOMOLOGY 

Dirofilaria repens, Railliet and Henry, 1911 

In the adult stage this nematode, which is a very similar parasite to 
D. immitis, occurs in the subcutaneous connective tissue of the dog. Its 
larvae enter the blood stream whence they are liable to be ingested by 
blood-sucking insects. According to Bernard and Bauche (1913) the 
yellow fever mosquito Aedes argent eus (Stegomyia calopus) acts as the 
intermediate host. These investigators while admitting that other species 
of mosquitoes might act as intermediate hosts of D. repens, found that 
A. argent eus best fulfilled the natural conditions for the transmission 
of the parasite, and their experiments were carried out with this species 
of mosquito. They followed the various stages in the development of 
the larval nematodes in mosquitoes fed experimentally upon infested dogs. 
About 2 days after the mosquito has been fed the nematode larvae leave 
the lumen of the alimentary tract and penetrate into the Malpighian 
tubules where they undergo most of their growth and development. By 
the eighth day the larvae may be found in some cases to have migrated 
into the body cavity and thoracic muscles and the last stage of develop- 
ment in mosquitoes may be found in the proboscis as early as the ninth 
day. Six young dogs (10 days old) were submitted to the bites of 
A. argent eus (fed 10 to 15 days previously on infected dogs) every morn- 
ing for fifteen days. Six young dogs of the same age were kept as con- 
trols, not exposed to mosquito bites. The bitten dogs all died within 
thirty days. Ecchymotic spots were found beneath the skin at the points 
of the mosquito bites, but no filarias were discovered. The other dogs all 
survived the experiment. Under natural conditions the youngest dogs 
found infested with D. repens by Bernard and Bauche were at least a 
year old, hence the writers conclude that the development of the parasite 
is very slow. Although they did not succeed in completing their experi- 
ments by recovering the adult stage of the parasite in dogs, following 
bites by infected mosquitoes, it appears safe to conclude that D. repens 
is transmitted by mosquitoes in a manner similar to that in which D. 
immitis is transmitted. 

Acanthocheilonema perstans (Manson, 1891) Railliet, Henry and 

Langeron, 1912 

This parasite occurs in man in tropical Africa and British Guiana, 
the adults in the intraperitoneal connective tissue and fatty tissue of the 
abdominal viscera and pericardium, and the first-stage larvae in the 
blood stream. The larvae exhibit no periodicity in their appearance in 
the circulation, the name perstans having reference to this fact. 

Christy (1903) has suggested that Ornithodoros moubata may act as 



RELATION OF INSECTS TO THE PARASITIC WORMS 75 

the intermediate host of Acanthocheilonema perstans. Wellman (1907) 
has reported that the larvae of this parasite are taken up by Ornithodoros 
moubata and according to his statements develop very slowly in this 
tick, advanced stages not being found until more than two months after 
infection of the tick. The suggestion made by Feldmann (1905), influ- 
enced by Bastian (1904), that the larvae of A. perstans may pass out 
of the body of the tick with its eggs into bananas and afterwards being 
swallowed with this fruit by human beings is a mode of infection which 
requires no consideration as a possibility without more supporting evi- 
dence than has yet been advanced. 

Hodges (1902) observed Filaria larvae in the thoracic muscles of 
the mosquitoes, Panoplites sp. and Aedes argent ens (Stegomyia calopus), 
three days after they had been fed on perstans blood. Low (1903) was 
able in one case to obtain development of perstans larvae to the sausage 
stage in a mosquito (Chrysoconops fuscopennatus) . Fulleborn (1908, 
1913) obtained a similar development in Anopheles maculipennis. Fiille- 
born and Low obtained negative results with various species of mosquitoes, 
sand fleas, lice and simuliids. 

Acanthocheilonema grassii (Noe, 1907) Railliet, Henry and 
Langeron, 1912 

The adults of this nematode occur in the subcutaneous and intermus- 
cular connective tissue and peritoneal cavity of the dog. The larvae 
produced by the females are unusually large, about twice as long and 
thick as the average filaria larva, and according to Noe (1907, 1908) 
do not pass into the blood stream as is generally the case among the 
filarias. Noe assumed that the larvae are restricted to the lymphatic 
system, and accordingly concluded that the intermediate host would most 
likely be a tick or similar slow feeding ectoparasite. In fact he found 
nematode larvae corresponding to those of A. grassii in Rhipicephalus 
sanguineus, a tick of common occurrence in regions where the dogs are 
infested with the nematode in question. Furthermore he states that all 
of the ticks attached to dogs infested with the nematode become infested 
with the larval worms. Additional evidence that R. sanguineus acts as 
the intermediate host is that the larvae in the ticks undergo growth and 
development, at least one molting period having been observed between 
successive stages. As R. sanguineus is a tick which falls to the ground to 
transform from the nymphal to the adult stage, the necessary opportunity 
is afforded for the transmission of A. grassii from one dog to another. 
Noe remarks that the nymph of this tick ingests large quantities of 
lymph. The larval nematodes taken in with the ingested lymph penetrate 
the intestinal wall into the body cavity where they undergo the develop- 



76 SANITARY ENTOMOLOGY 

merit necessary before they are ready to be returned to the definitive host, 
after transformation of the nymphal tick to the adult stage. Noe be- 
lieves that the dog becomes infected during the initial phase of attach- 
ment of the adult. He also suggests that adult males which, unlike adult 
females, may pass from one host to another are capable of acquiring 
infection from one dog and transferring it to another. He has found 
as many as 22 larvae of A. grassii in one male tick. Noe is of the 
opinion that the larvae escape through thin portions of the cuticle of 
the mouth parts of the tick and thus reach the final host in a way similar 
to that followed by the larvae of D. immitis and other filarias trans- 
mitted by mosquitoes. 

It is of interest to note that Grassi and Calandruccio (1890) found 
larval nematodes in Rhipicephalus siculus (-R. sanguineus) which they 
identified as the larvae of Fttaria recondita (= Acanthocheilonema recon- 
ditum). Noe thinks that these larvae may have been A. grassii rather 
than A. reconditum. 

Evidently further investigations into the life history of A. grassii are 
necessary before ticks can be accepted as the intermediate host of this 
parasite. 



Acanthocheilonema reconditum (Grassi, 1890) Railliet, Henry and 

Langeron, 1912 

This nematode is a parasite of the dog and in the adult stage has been 
collected from adipose tissue in the neighborhood of the kidney. Accord- 
ing to Grassi and Calandruccio (1890) the first-stage larvae occur in the 
blood stream, and are the so-called Haematozoa of Lewis which have 
been seen by many observers, first by Gruby and Delafond (1843), after- 
wards by Lewis and others. Apparently, however, the larvae seen in 
the blood of dogs by Grassi and Calandruccio as well as those known 
as Lewis's Haematozoa are in reality the larvae of Dirofilaria repens. 
Grassi and Calandruccio describe various stages of nematode larvae 
found in fleas (Ctenocephalus canis, C. felis, and Pulex irritans) and in a 
tick (Rhipicephalus siculus=R. sanguineus) as developmental stages in 
the life history of A. reconditum. According to Noe (1907, 1908), the 
larvae found in R. sanguineus by Grassi and Calandruccio were probably 
those of Acanthocheilonema grassii. 

Owing to the confusion existing with reference to the identity of the 
parasite that Grassi and Calandruccio studied, the species to which the 
larval nematodes observed in fleas belong, is uncertain. Grassi and Calan- 
druccio's experiments can not be considered conclusive so far as con- 
cerns the life history of A. reconditum. 



RELATION OF INSECTS TO THE PARASITIC WORMS 77 

Set aria labiato-papillosa (Alessandrini, 1838) Railliet and Henry, 1911 

The adults of this nematode are common parasites in the peritoneal 
cavity of cattle in various parts of the world including the United States. 
The larvae enter the blood stream, and Noe (1908) identifies certain 
larval nematodes found in Stomoocys calcitrans as belonging to this 
species. That this fly actually serves as the intermediate host, however, 
remains to be proved. 

The possibility is not excluded that Noe mistook Habronema larvae 
for the larvae of S. labiato-papillosa. 

Oncocerca 

About twelve species of this genius have been described. Onco- 
cerca volvulus in the adult stage occurs in nodular tumors beneath the 
skin of man in Africa. Oncocerca caecutiens is found in subcutaneous 
nodules on the head among natives living at a certain altitude on the 
west coast of Guatemala and is the cause of so-called "Coast erysipelas." 
O. gibsoni causes worm nodules in the brisket and other locations in 
cattle in Australia. Two species occur in cattle in the United States: 
one undetermined species is found in relation with the ligaments of the 
legs and neck, the other (0. lienalis) is found in the gastrosplenic liga- 
ment. Oncocerca larvae have not been found in the blood stream but 
may be recovered from the lymph spaces in the neighborhood of the adult 
worms. The intermediate hosts of these nematodes are unknown but biting 
insects have been suspected. The results of experiments have been nega- 
tive. Brumpt (1903) has suggested the possibility that Glossina palpalis 
acts as intermediate host of 0. volvulus. 

Robles (1919) suggests that two species of Simulium (close to S. 
dinelli and S. samboni) may be involved as vectors of 0. caecutiens in 
view of the fact that these flies are most numerous in the places where 
the largest number of cases of Oncocerca occur. Furthermore these 
species of flies are absent in lower altitudes corresponding with the absence 
of Oncocerca. 

3. Other Nematodes 

Different investigators have recorded the occurrence of larval nema- 
todes of unknown species in various insects. Usually these have been 
very poorly described and it is questionable in many cases whether 
if found again they could be recognized as the same forms. Some of 
them may be the larval forms of nematodes whose adults are already 
known as parasites of higher animals. Among such larvae of uncertain 
identity may be mentioned Filaria geotrupis in the abdominal cavity 



78 SANITARY ENTOMOLOGY 

of Geotrupes stercorarius (possibly the larva of Physocephalus sexala- 
tus), Filaria ephemeridarum in the abdominal cavity of the larvae of 
Ephemera vulgata and Oligoneuria rhenana, Filara rytipleuritis (of 
Magalhaes, 1900, not Deslongchamps, 1824) in the abdominal cavity of 
Periplaneta americana (possibly a Gongylonema according to Seurat), 
Filaria stomoxeos in Stomoxys calcitrans (possibly the larva of Hab- 
ronema microstoma), Mastophorus echiurus, and Cephalacantlius mona- 
canthus in Tenebrio molitor (probably larvae of Protospirura muris), 
Mastophorus globocaudatus and Cephalacanthus triacanthus in 
Geotrupes stercorarius (possibly larvae of Physocephalus sexalatus). 

4. Mermithidae 

These worms which resemble the nematodes and are usually grouped 
with them are not known to be of importance in medical zoology. One 
species, of uncertain identity, is of interest, however, as it is the so-called 
"cabbage snake" whose presence among the leaves of cabbage has alarmed 
people who have encountered it. This worm, like others of the same 
family, undoubtedly passes through a portion of its development in the 
body of an insect, probably one of the common caterpillars that attack 
cabbage. Similar worms have been found in apples. 

GORDIACEA OR HORSE-HAIR WORMS 

The Gordiacea or horse-hair worms (as which they are popularly 
known from the superstitious belief that they are animated horse hairs) 
are of medical interest because several species have been recorded as 
parasites of man. They gain entrance to the alimentary tract by being 
swallowed in drinking water. The adults are of not uncommon occur- 
rence in springs and other surface waters. When swallowed by human 
beings they are usually soon vomited up but they have in some cases 
apparently survived in the intestine for several months before they were 
finally expelled. In some species, and probably in all, insects serve as 
hosts for the larval stages. The adults deposit their eggs in the water 
in which they live. The larvae hatching from the eggs enter the bodies 
of insects such as grasshoppers (as for example, in the case of Gordius 
robustus) or crickets (as for example, in the case of Paragordius varius) 
or in the case of other species they may enter aquatic insect larvae, 
which may later be devoured by carnivorous water insects. In the latter 
the worms undergo their development until they have reached or ap- 
proached maturity when they burst out of the infested insect and escape 
into the water. The following species of Gordiacea have been recorded 
as accidental parasites of man: Gordius aquaticus, G. chilensis, Para- 



RELATION OF INSECTS TO THE PARASITIC WORMS 79 

gordius varius (a common American species), Paragordius tricuspidatus, 
Parachordodes tolusanus, Parachordodes violaceus, Parachordodes pus- 
tulosus, and Chordodes alpestris. 

ACAXTHOCEPHALA OR THORN-HEADED WORMS 

This highly specialized group of parasites, commonly classified in the 
Nemathelminthes, with which it has little in common beyond a superficial 
resemblance in the general shape of the body, has been but little studied. 
Most of the known species are parasitic in birds. 

Macracanthorliynclius hirudinaceus (Pallas, 1781) Travassos, 1916 

This worm in the adult stage (sometimes called the giant thorn- 
headed worm) is a common parasite of the intestine of the pig and is said 
to occur as a parasite of man along the Riyer Volga. Its eggs pass out 
of the body of the host in the feces. Swallowed by certain insects [larvae 
of Melolontha melolontha, Cetonia aurata, Pliyllopliaga arcuata (Lach- 
nosterna), and Diloboderus abderu*s~\ the eggs hatch, and the larvae 
develop into an intermediate stage, which in turn completes its develop- 
ment to maturity when the infested grub is eaten by a pig. 

Moniliformis moniliformis (Bremser, 1819) Travassos, 1915 

This parasite in its adult stage (sometimes called the beaded thorn- 
headed worm) is of common occurrence in the intestine of rats and other 
rodents in tropical and subtropical regions, and has been found in man 
in Italy. The life cycle is similar to that of the giant thorn-headed worm 
except for the difference in hosts. According to Grassi and Calandruccio 
(1888), Blaps mucronata acts as an intermediate host. According to 
Magalhaes (1898) and Seurat (1912), the usual intermediate host is a 
cockroach (Periplaneta americana). 

COMPENDIUM OF PARASITES ARRANGED ACCORDING TO INSECT HOSTS 2 

Aphaniptcra (Siphonaptera) — fleas 

Ceratophyllus fasciatus Bosc 
Hymenolepis diminwta 
? Hymenolepis nana 

Ctenocephalus canis Curtis 

? Acanthocheilonema reconditum 
2 The scientific names of the insects have been revised bv the editor. 



80 SANITARY ENTOMOLOGY 

Dipylidium caninum 
Hymenolepis diminuta 

Ctenocephalus felis Bouche 

? Acanthocheilonema reconditum 
? Dipylidium caninum 

Pulex irritans Linnaeus 

? Acanthocheilonema reconditum 
Dipylidium caninum 
Hymenolepis diminuta 

Xenopsylla cheopis Rothschild 
Hymenolepis diminuta 
? Hymenolepis nana 
? Protospirura muris 

Diptera — flies 

Aedes argenteus Poirret (Stegomyia calopus Meigen) 

Acanthocheilonema perstans (incomplete development) 
Dirofilaria repens 
Filaria bancrofti 

Filaria demarquayi (incomplete development) 
? Filaria tucumana 

Aedes gracilis Leicester (Stegomyia) 
Filaria bancrofti 

Aedes scutellaris Walker (Culex albopictus Skuse) 
Filaria bancrofti 

Anopheles barbirostris Van der Wulp (Myzorhynchus) 
Filaria bancrofti 

Anopheles bifurcatus Linnaeus 
Dirofilaria immitis 

Anopheles costalis Loew (Pyretophorus) 
Filaria bancrofti 

Anopheles maculipennis Meigen (claviger Fabricius) 

Acanthocheilonema perstans (incomplete development) 

Dirofilaria immitis 

Filaria demarquayi (incomplete development) 

Trematode 






RELATION OF INSECTS TO THE PARASITIC WORMS 81 

Anopheles rossi Giles (Myzomyia) 
Trematode 
Filaria bancrofti 

Anopheles sinensis Wiedemann (Myzorhynchus) 
Filaria bancrofti 

Anopheles sinensis peditaeniatus Leicester (Myzorhynchus) 
Filaria bancrofti 

Anopheles sinensis pseudopictus Grassi (Myzorhynchus) 
Dirofilaria immitis 

Anopheles superpictus Grassi (Myzomyia) 
Dirofilaria immitis 

Chironomus plumosus Linnaeus 
Lecithodendrium ascidia 

Chrysoconops fuscopennatus (Theobald) (Taeniorhynchus) 
Acanthocheilonema perstans (incomplete development) 

Chrysops spp. 

Filaria (Loa) loa 

? Chrysops centurionis Austen 
Filaria (Loa) loa 

? Chrysops dimidiata Van der Wulp 
Filaria (Loa) loa 

? Chrysops longicornis Macquart 
Filaria (Loa) loa 

Culex gelidus Theobald 
Filaria bancrofti 

Culex malariae Grassi 
Dirofilaria immitis 

Culex penicillaris Rondani 
Dirofilaria immitis 



82 SANITARY ENTOMOLOGY 

Culex pipiens Linnaeus 
Dirofilaria immitis 
Filaria bancrofti 

Culex quinquefasciatus Say (skusei Giles) (fatigans Wiedemann) 
Filaria bancrofti 

Culex sitiens Wiedemann 
Filaria bancrofti 

Mansonioides annulipes Theobald 
Filaria bancrofti 

Mansonioides uniformis Theobald 
Filaria bancrofti 

Musca domestica Linnaeus 

Choanotaenia infundibulum 
Habronema muscae 
Habronema microstoma 
Habronema megastoma 
? Davainea cesticillus 
? Davainea tetragona 

Panoplites sp. 

Acanthocheilonema perstans (incomplete development) 

Scutomyia albolineata Theobald 
Filaria bancrofti 

Stomoxys calcitrans Linnaeus 

Filaria stomoxeos 

Habronema microstoma 
? Habronema muscae 
? Setaria labiato-papillosa 
? Hymenolepis carioca 

Taeniorhynchus domesticus Leicester 
Filaria bancrofti 



Neuroptera 



Sialis lutaria (Linnaeus) 
Trematode 



RELATION OF INSECTS TO THE PARASITIC WORMS 83 

Trichoptera — hairy-winged insects 

Anabolia nervosa (Leach) Curtis 
Allocreadium isoporum 
Opisthioglyphe rastellus 

Chaetopteryx villosa (Fabricius) 
Allocreadium isoporum 

Drusus trifidus McLachlan 
Trematode 

Limnophilus flavicornis (Fabricius) 
Opisthioglyphe rastellus 

Limnophilus griseus (Linnaeus) 
Opisthioglyphe rastellus 

Limnophilus lunatus (Curtis) 
Opisthioglyphe rastellus 

Limnophilus rhombicus (Linnaeus) 
Opisthioglyphe rastellus 

Mystacides nigra (Linnaeus) 
Trematode 

Notidobia ciliaris (Linnaeus) 
Trematode 

Phryganea grandis 
Trematode 

Phryganea sp. 

Lecithodendrium chilostomum 

Rhyacophila nubila Zetterstedt 
Trematode 



Lepidoptera — moths, butterflies 

Asopia farinalis (Linnaeus) 
Hymenolepis diminuta 

Nymphula nymphaeata (Linnaeus) (Hydrocampa) 
Trematode 



84 SANITARY ENTOMOLOGY 

Coleoptera — beetles 

Akis goryi (Solier) 

Spirocerca sanguinolenta 
Spirura gastrophila 

Akis spinosa (Linnaeus) 
Hymenolepis dimmuta 

Aphodius rufus (Moll) var. castaneus Marsh 
A r duenna strong ylina 

Aphodius coloradensis Horn 
Gongylonema scutatum 

Aphodius femoralis Say 

Gongylonema scutatum 

Aphodius fimetarius Linnaeus 
Gongylonema scutatum 

Aphodius granarius Linnaeus 
Gongylonema scutatum 

Aphodius vittatus Say 

Gongylonema scutatum 

Blaps appendiculata 

Gongylonema sp. (G. scutatum according to Seurat) 

Blaps sp. 

Gongylonema brevispiculum 

Blaps sp. (near appendiculata) 
Spirura gastrophila 
Gongylonema sp. (G. scutatum according to Seurat) 

Blaps emondi 

Gongylonema sp. (G. scutatum according to Seurat) 

Blaps mucronata Latreille 

Moniliformis moniliformis 

Blaps strauchi Reiche 

Spirura gastrophila 

Gongylonema sp. (G. scutatum according to Seurat) 



RELATION OF INSECTS TO THE PARASITIC WORMS 85 

Cetonia aurata (Linnaeus) 

M acracanthorhynchus hirudinaceus 

Copris hispanus (Linnaeus) 
Spirocerca sanguinolenta 

Diloboderus abderus Sturm 

M acracanthorhynchus hirudinaceus 

Geotrupes douei Gory 

? Gongylonema mucronatum 
Spirocerca sanguinolenta 
Physocephalus sexalatus 

Geotrupes stercorarius (Linnaeus) 
Cephalacanthus triacanthus 
Filaria geotrupis 
Mastophorus globocaudatus 
? Physocephalus sexalatus 

Gymnopleurus mopsus (Pallas) 
? Gongylonema mucronatum 

Gymnopleurus sturmi Mac Leay 
? Gongylonema mucronatum 
Spirocerca sanguinolenta 

Ilybius fuliginosus (Fabricius) 
Haplometra cylmdracea 

Melolontha melolontha Linnaeus (vulgaris Fabricius) 
M acracanthorhynchus hirudinaceus 

Chironitis irroratus Rossi (Onitis) 
? Gongylonema mucronatum 

Onthophagus spp. 

Arduenma strongylina 
Spirura gastrophila 

Onthophagus bedeli Neitt. 
? Gongylonema mucronatum 
Physocephalus sexalatus 



86 SANITARY ENTOMOLOGY 

Onthophagus hecate Panzer 
Gongylonema scutatum 

Onthophagus nebulosus Reiche 
Physocephalus sexalatus 

Onthophagus pennsylvanicus Harold 
Gongylonema scutatum 

Phyllophaga arcuata Smith (Lachnosterna) 
M acracanthorhynchus hirudinaceus 

Scarabaeus (Ateuchus) sacer Linnaeus 
? Gongylonema mucronatum 
Physocephalus sexalatus 
Spirocerca sanguinolenta 

Scarabaeus (Ateuchetus) variolosus Fabricius 
Physocephalus sexalatus 
? Spirocerca sanguinolenta 

Scaurus striatus Fabricius 
Hymenolepis diminuta 

Tenebrio molitor Linnaeus 

Cephalacanthus monacanthus 
Gongylonema neoplasticum 
Hymenolepis diminuta 
? Hymenolepis microstoma 
Mastophorus echiurus 
Protospirura muris 

Water beetles 

Pleurogenes claviger 
Pleuro genes medians 
Prosotocus confusus 

Mallophaga — bird lice 

Leiothinae ( ? genus ? species) 
Filaria cypseli 

Trichodectes latus Nitzsch (canis DeGeer) 
Dipylidium caninum 



RELATION OF INSECTS TO THE PARASITIC WORMS 87 

1 so pt era — termites 

Hodotermes pretoriensis Fuller 
Filaria aallinarum 



Odonata — dragonflies 

Aeschna sp. 

Prosotocus confusus 

Agrion sp. 

Gorgodera pagenstecheri 
Gorgodera varsoviensis 
Pleurogenes medians 

Calopteryx virgo (Linnaeus) 
Halipegus ovocaudatus 
Pneumonoeces similis 

Cordulia sp. 

Prosotocus confusus 

Epitheca spp. 

Gorgodera cygnoides 
Gorgodera pagenstecheri 
Gorgodera varsoviensis 



Plectoptera — mayflies 

Cloeon dipterum (Linnaeus) Stephens 
? Opisthioglyphe rastellus 

Ephemera vulgata Linnaeus 
Allocreadium isoporum 
Filaria ephemeridarum 
? Opisthioglyphe rastellus 

Ephemeridae 

Lecithodendrium ascidia 



Oligoneuria rhenana Imhoff 
Filaria ephemeridarum 



88 SANITARY ENTOMOLOGY 

Plecoptera — stoneflies 
Perlidae 

Lecithodendrium ascidia 
Trematode 

Orthoptera — cockroaches, etc. 

Blattella germanica (Linnaeus) Caudell 
Gongylonema neoplasticum 
Gongylonema scutatum (experimental infection) 

Periplaneta americana (Linnaeus) Burmeister 
Filaria rytipleuritis of Magalhaes, 1900 
Gongylonema neoplasticum 
Moniliformis moniliformis 

Blatta orientalis Linnaeus 

Gongylonema neoplasticum 
? Spirocerca sanguinolenta 
Spirura gastrophila 

Dermaptera — earwigs 

Anisolabis annulipes Lucas 
Hymenolepis diminuta 

Myriapoda — millipedes, centipedes 3 

Fontaria virginiensis (Drury) 
Hymenolepis diminuta 

Glomeris limbata 

Tapeworm larvae 

Julus sp. 

Hymenolepis dimmuta 

Julus guttulatus 

Nematode larva 

Acarina — ticks, mites 3 

Ixodes ricinus (Linnaeus) Latreille 
? Filaria martis 
3 Included in list because of their similarity to insects. 



RELATION OF INSECTS TO THE PARASITIC WORMS 89 

Ornithodoros moubata (Murray) 
? Acanthocheilonema perstans 

Rhipicephalus sanguineus (Latreille) 
? Acanthocheilonema grassii 
? Acanthocheilonema reconditum 

Isopoda — sowbugs 4 

Porcellio laevis Latreille 
? Acuaria spiralis 

LIST OF REFERENCES 

Ackert, James E. 

1918. — On the life cycle of the fowl cestode, Davainea cesticillus 

(Molin). (Preliminary communication.) Jour. Parasit. Ur- 

bana, 111., Vol. 5, No. 1, Sept., pp. 41-43, pi. 5, figs. 1-4. 
1919. — On the life history of Davainea tetragona (Molin), a fowl 

tapeworm. Jour. Parasit., Urbana, 111., Vol. 6, No. 1, Sept., 

pp. 28-34. 

Ashburn, P. M., and Craig, Charles F. 

1907. — Observations upon Filaria philippvnensis and its development 
in the mosquito. Philippine Journ. Sci., vol. 2B, No. 1, Mar., 
pp. 1-14, pis. 1-7, figs. 1-26. 

Baldasseroni, Vincenzo. 

1909. — "Ixodes ricinus" L. infetto da embrioni di Filaria. Bull. Soc. 
Entom. Ital., vol. 40, Nos. 3-4, pp. 171-174, Dec. 30. 

Bancroft, Thomas L. 

1901. — Preliminary notes on the intermediate host of Filaria immitis 
Leidy. Journ. Trop. Med. Lond., vol. 4, Oct. 15, pp. 347-349. 

Bastian, H. Charlton. 

1904. — Note on the probable mode of infection of the so-called Filaria 
perstans, and on the probability that this organism really 
belongs to the genus Tylenchus (Bastian). Lancet, vol. 166, 
No. 4196, vol. 1, No. 5, Jan. 30, pp. 286-287, figs. 1-3. 

Bernard, P. Noel, and Bauche, J. 

1913. — Conditions de propagation de la filariose sous-cutanee du chien. 
Stegomyia fasciata hote intermediaire de Diroflaria repens. 
Bull. Soc. Path. Exot., vol. 6, No. 1, Jan. 8, pp. 89-99, figs. 1-9. 
4 Included in list because of their similarity to insects. 



90 SANITARY ENTOMOLOGY 

Biglieri, R., and Araoz, J. M. 

1917. — Contribucion al estudio de una nueva filariosis humana encon- 
trada en la Republica Argentina (Tucuman), ocasionada por la 
"Filaria tucwmana." 1. Confer. Soc. sud-am. de hig. [etc.], 
Buenos Aires Sept. 17-84., 1916, pp. 403-422. 

Brumpt, Emile. 

1903. — Sur role des mouches tse-tse en pathologie exotique. Compt. 
Rend. Soc. Biol., vol. 55, No. 34, Dec. 4, pp. 1496-1498, 

Bull, Lionel B. 

1916. — A granulomatous affection of the horse — Habronemic granu- 
lomata (cutaneous habronemiasis of Railliet). Journ. Comp. 
Path, and Therap., vol. 29, No. 3, Sept, 30, pp. 187-199, figs. 
1-5. 
1919. — A contribution to the study of habronemiasis : A clinical, 
pathological, and experimental investigation of a granulomat- 
ous condition of the horse-habronemic granuloma, pp. 85-141, 
pis. 13-15, figs. 1-8. [Reprint from Tr. Roy. Soc. South 
Australia, v. 43.] 

Christy, Cuthbert. 

1903. — The distribution of sleeping sickness, Filaria perstans, etc., 
in East Equatorial Africa. (Preliminary report dated Oct. 
31, 1902). Roy. Soc. Rep. Sleep.-Sick. Comm., No. 2, Nov., 
pp. 3-8, 3 maps. 

De Magalhaes, Pedro Severiano. 

1898. — Notes d'helminthologie bresilienne. [5. note] Arch. Parasitol., 

vol. 1, No. 3, July, pp. 361-368, figs. 1-4. 
1900. — Notes d'helminthologie bresilienne. [8. note] Arch. Parasitol., 
vol. 3, No. 1, May 15, pp. 34-69, figs. 1-25. " 

Descazeaux, J. 

1915. — Contribution a l'etude de P "esponja" ou plaies d'ete des 
equides du Bresil. (Rapport de Railliet, 17 juin). Bull. Soc. 
Centr. de Med. Vet., vol. 69, Jan. 30-Sept. 30, pp. 468-486, figs. 
1-3. 

Deslongchamps, Eugene Eudes. 

1824.— Filaire. Filaira. Encycl. Methodique, vol. 2, pp. 391-397. 



RELATION OF INSECTS TO THE PARASITIC WORMS 91 

Dutton, J. Everett. 

1905. — The intermediary host of Filaria cypseli (Annett, Dutton, El- 
liott) ; the Filaria of the African swift, Cypselus affinis. 
Thompson Yates & Johnston Lab. Rep., Lond., n. s., vol. 6, 
No. 1, Jan., pp. 137-147, pi. 5, figs. i-x. 

Feldmann. 

1905. — Ueber Filaria per stems im Bezirk Bukoba. Arch. f. Schiffs- u. 
Tropen-Hyg., vol. 9, No. 2, Feb., pp. 62-65, 2 pis. 

Fibiger, Johannes, and Ditlevsen, Hjalmar. 

1914. — Contributions to the biology and morphology of Spiroptera 
(Gongylonema) neoplastica n. s. Mindeskr. Japetus Steen- 
strups Fodsel, 2. Halvbind, 28 pp., figs. 1-3, pis. 1-4, figs. 1-32. 

Fulleborn, Friedrich. 

1908. — Ueber Versuche an Hundefilarien und deren Ubertragung durch 
Miicken. Beihefte (8) z. Arch. f. Schiffs- u. Tropen-Hyg., 
vol. 12, Nov., pp. 313-351 (43 pp.), figs. 1-6, pis. 1-4, figs. 
1-38. ■ 

1908.- — Untersuchungen an menschlichen Filarien und deren Uber- 
tragung auf Stechmucken. Beihefte (9) z. Arch. f. Schiffs- u. 
Tropen-Hygr., vol. 12, Nov., pp. 357-388 (36 pp.), figs. 1-3, 
pis. 1-7, figs. 1-132. 

1913. — Die Filarien des Menschen. Handb. d. path. Mikroorganism. 
(Kolle & Wassermann), Jena, 2. Aufl., vol. 8, pp. 185-344, figs. 
1-41, pis. 1-6. 

Galeb, Osman. 

1878. — Observations et experiences sur les migrations du Filaria 
rytiplewrites, parasite des blattes et des rats. Compt. Rend. 
Acad. Sc, vol. 87, No. 2, July 8, pp. 75-77. 

Grassi, Giovanni Battista. 

1887. — Entwickelungscyklus der Tarda nana. Dritte praliminarnote. 

Centralbl. f. Bakteriol. (etc.), Jena, 1. Jahr., vol. 2, No. 11, 

pp. 305-312. 
1888. — Ciclo evolutivo della Spiroptera {Filaria) sanguinolenta. Gior. 

di Anat., Fisiol. e Patol. d. Animali, vol. 20, No. 2, Mar.-Apr., 

pp. 99-101. 

Grassi, Giovanni Battista, and Calandruccio, Salvatore. 

1888. — Ueber einen Echinorhynchws, welcher auch im Menschen para- 
sitirt und dessen Zwischenwirth ein Blaps ist. Centralbl. f. 






92 SANITARY ENTOMOLOGY 

Bakteriol. (etc.), Jena, 2. Jahr., vol. 3, No. 17, pp. 521-525, 
figs. 1-7. 
1890. — Ueber Haematozoon Lewis. Entwickelungscyklus einer Filaria 
(FUaria recondita Grassi) des Hundes. Centralbl. f. Bakteriol. 
(etc.), Jena, vol. 7, No. 1, Jan. 2, pp. 18-26, figs. 1-16. 

Grassi, Giovanni Battista, and Rovelli, Giuseppe. 

1888. — Intorno alio sviluppo cestodi. Nota preliminare. Atti R. 

Accad. d. Lincei, Roma, Rendic, an. 285, 4. s., vol. 4, 1. 

semestre, No. 12, June 3, pp. 700-702. 
1888. — Bandwiirmerentwickelung. Centralbl. f. Bakteriol. (etc.), 

Jena, 2. Jahr, vol. 3, No. 6, p. 173. 
1889. — Sviluppo del cisticerco e del cisticercoide. Nota preliminare. 

Atti R. Accad. d. Lincei, Roma, Rendic, an. 286, 4. s., vol. 

5, 1. semestre, No. 3, Feb. 3, pp. 165-174, figs. 1-4. 
1892. — Ricerche embriologiche sui cestodi. Atti Accad. Giornia di 

Sc. Nat. in Catania (1891-92), an. 68, 4. s., vol. 4, 2. mem., 108 

pp., 4 pis. 

Gruby, David, and Delafond, Henri-Mamert-Onesius. 

1843. — Note sur une alteration vermineuse du sang d'un chien deter- 
minee par un grand nombre d'hematozoaires du genre filaire. 
Compt. Rend. Acad. Sc, vol. 16, No. 6, Feb. 6, pp. 325-326. 

Guberlet, John E. 

1916. — Morphology of adult and larval cestodes from poultry. Trans. 

Am. Micr. Soc, vol. 35, No. 1, Jan., pp. 23-44, pis. 5-8, figs. 

1-30. 
1919. — On the life history of the chicken cestode, Hymenolepis carioca 

(Magalhaes). Journ. Parasit., vol. 6, No. 1, Sept., pp. 

35-38, pi. 4, figs. 1-6. 

Hill, Gerald F. 

1918. — Relationship of insects to parasitic diseases in stock. Pp. 11- 
107, pis. 2-8, figs. 1-49A. 8°. Melbourne. [Reprint from 
Proc Roy. Soc. Victoria, new ser., v. 31, pt. 1.] 

Hodges, Aubrey. 

1902. — Sleeping-sickness and Filaria perstans in Busoga and it's neigh- 
borhood, Uganda Protectorate. Journ. Trop. Med., vol. 5, No. 
19, Oct. 1, pp. 293-300, 1 map, 1 pi., figs. 1-2. 

Johnston, T. Harvey. 

1913. — Notes on some Entozoa. Proc. Roy. Soc. Queensland, vol. 24, 
pp. 63-91, pis. 2-5, figs. 1-45. (Advance separate issued Nov. 
1, 1912). 



RELATION OF INSECTS TO THE PARASITIC WORMS 93 

Joyeux, Ch. 

1916. — Sur le cycle evolutif de quelques cestodes. Note preliminaire. 
Bull. Soc. Path. Exot., vol. 9, No. 8, Oct. 11, pp. 578-583. 

Kleine, F. K. 

1915. — Die Ubertragung von Filarien durch Chrysops. Zeitschr. f. 
Hyg. u. Infektionskrankh., vol. 80, No. 3, Oct. 26, pp. 345-349. 

Lebredo, Mario G. 

1904. — Filariasis. Nota preliminar deducida de experiencias practicas, 

que demuestran el sitio por donde la Filaria nocturna abandona 

el Culex pipiens infectado. Rev. Med. Trop., Habana, vol. 5, 

No. 11, Nov., pp. 171-172. 
1905. — Metamorphosis of Filaria in the body of the mosquito (Culex 

pipiens). Journ. Infect. Dis., Suppl. (1), May, pp. 332- 

352, pis. 1-3, figs. 1-16. 

Leiper, Robert T. 

1913. — [Metamorphosis of Filaria loa.~\ [Telegram to London School 
Trop. Med., Dec. 27, 1912]. Lancet, No. 4662, vol. 184, 
vol. 1, No. 1, Jan. 4, p. 51. 

Leuckart, Karl Georg Friedrich Rudolph. 

1867. — Die menschlichen Parasiten und die von ihnen hernihrenden 
Krankheiten. Ein Hand- und Lehrbuch fur Naturforscher und 
Aerzte. Vol. 2, 1. Lief., vi, 256 pp., 158 figs. Leipzig & Heidel- 
berg. 

Low, George C. 

1902. — Notes on Filaria demarquaii. Brit. Med. Journ., No. 2143, 

vol. 1, Jan. 25, pp. 196-197. 
1903. — Filaria perstans. Brit. Med. Journ., No. 2204, vol. 1, Mar. 28, 
pp. 722-724, figs. 1-2. 

Manson, (Sir) Patrick. 

1878. — On the development of Filaria sanguinis hominis, and on the 
mosquito considered as a nurse. Journ. Linn. Soc. Lond., 
Zool. (75), vol. 14, Aug. 31, pp. 304-311. 
Marchi, Pietro. 

1867. — Monografia sulla storia genetica e sulla anatomia della 
Spiroptera obtusa Rud., 34 pp., 2 pis. fol. Torino. [Advance 
separate from Mem. R. Accad. Sc. Torino, CI. d. Sc. Fis., Mat. 
e Nat., 2. s., vol. 25, issued in 1871.1 



94 SANITARY ENTOMOLOGY 

Melnikov, Nicolaus. 

1869. — Ueber die Jugendzustande der Tpenia cwcwmerina. Arch. f. 
Naturg., Berl., 35. Jahr., vol. 1, No. 1, pp. 62-70, pi. 3, figs, 
a-c. 

Nickerson, W. S. 

1911. — An American intermediate host for Hymenolepis dimirmta* 
Science, n. s., No. 842, vol. 33, Feb. 17, p. 271. 

Nicoll, W., and Minchin, E. A. 

1911. — Two species of cysticercoids from the rat-flea (Ceratophyllus 
fasciatus). Proc. Zool. Soc. Lond., No. 1, Mar., pp. 9-13, 
figs. 1-2. 

Noe, Giovanni. 

1900. — Propagazione delle filarie del sangue esclusivamente per mezzo 

della puntura della zanzare. 2. Nota preliminare. Atti R. 

Accad. d. Lincei, Rendic. CI. di Sc. Fis., Mat. e Nat., an. 297, 

5. s., vol. 9, 2. semestre, No. 12, Dec. 16, pp. 357-362, figs. 1-3. 
1903. — Studi sul ciclo evolutivo della Filaria labiato-papillosa, Ales- 

sandrini. Nota preliminare. Atti R. Accad. d. Lincei, Rendic. 

CI. di Sc. Fis., Mat. e Nat., an. 300, 5. s., vol. 12, 2 semestre, 

No. 9, Nov. 8, pp. 387-393. 
1907. — La Filaria grassii, n. sp. e la Filaria recondita, Grassi. Nota 

preliminare. Atti R. Accad. d. Lincei, Rendic. CI. di Sc. Fis. 

Mat. e Nat., an. 304, 5. s., vol. 16, 2. semestre, No. 12, Dec. 

15, pp. 806-810. 
1908. — II ciclo evolutivo della Filaria grassii, mihi, 1907. Atti R. 

Accad. d. Lincei, Rendic. CI. di Sc. Fis., Mat. e Nat., an. 305, 

5. s., vol. 17, 1. semestre, No. 5, Mar. 1, pp. 282-293, figs. 1-4. 

Nuttall, George H. F. 

1899. — On the role of insects, arachnids, and myriapods as carriers 
in the spread of bacterial and parasitic diseases of man and 
animals. A critical and historical study. Johns Hopkins 
Hosp. Rep., Baltimore, vol. 8, Nos. 1-2, pp. 1-154, pis. 1-3. 

Piana, Giovanni Pietro. 

1897. — Osservazioni sul Dispharagus nasutus Rud. dei polli e sulle 
larve nematoelmintiche delle mosche e dei porcellioni. Atti 
Soc. Ital. Sc. Nat. (etc.), Milano, vol. 36, No. 3-4. Feb., pp. 
239-262, figs. 1-21. 



, 



RELATION OF INSECTS TO THE PARASITIC WORMS 95 

Ransom, Brayton H. 

1911. — The life history of a parasitic nematode — Habronema muscae. 

Science n. s., No. 881, vol. 34, No. 17, pp. 690-692. 
1913. — The life history of Habronema muscae (Carter), a parasite 
of the horse transmitted by the house fly. U. S. Dept. Agric, 
Bureau Animal Indust., Bull. 163, Apr. 3, pp. 1-36, figs. 1-41. 

Ransom, Brayton H., and Hall, Maurice C. 

1915. — The life history of Gongylonema scutatum. Journ. Parasit., 

vol. 1, No. 3, Mar., p. 154. 
1916. — The life history of Gongylonema scutatum. Journ. Parasit., 

vol. 2, No. 2, Dec, 1915, pp. 80-86. 
1917. — A further note on the life history of Gongylonema scutatum. 

Journ. Parasit., vol. 3, No. 4, June, pp. 177-181. 

Ringenbach, J., and Guyomarc'h. 

1914. — La filariose dans les regions de la nouvelle frontiere Congo- 
Cameroun. Observations sur la transmission de Microfilaria 
diurna et de Microfilaria perstans. Bull. Soc. Path. Exot., 
vol. 7, No. 7, July 8, pp. 619-626. 

Robles, R. 

1919. — Onchocercose humaine au Guatemala produisant la cecite et 
'"l'erysipele du littoral" (erisipela de la costa). Bull. Soc. 
Path. Exot., vol. 12, No. 7, July 9, pp. 442-460, 2 maps, 
figs. 1-6. 

Seurat, L. G. 

1912. — Sur le cycle evolutif du spiroptere du chien. Compt. Rend. 

Acad. Sc, vol. 154, No. 2, Jan. 8, pp. 82-84. 
1912. — La grande blatte, hote intermediaire de Techinorhynque 

moniliforme en Algerie. Compt. Rend. Soc. Biol., vol. 72, No. 

2, Jan. 19, pp. 62-63. 
1913. — Sur l'evolution du Physocephalus sexalatus (Molin). Compt. 

Rend. Soc. Biol., vol. 75, No. 35, Dec. 12, pp. 517-520, figs. 

1-4. 
1913. — Sur revolution du Spirura gastrophila Mull. Compt. Rend. 

Soc. Biol., vol. 74, No. 6, Feb. 14, pp. 286-289, figs. 1-3. 
1916. — Contribution a l'etude des formes larvaires des nematodes 

parasites heteroxenes. Bull. Scient. France et Belg., 7. s., 

vol. 49, No. 4, July 6, pp. 297-377, figs. 1-14. 
1918. — Extension de l'habitat du Spirura gastrophila (Mueller). 

Compt. Rend. Soc. Biol., vol. 81, No. 15, July 27, pp. 789-791. 



96 SANITARY ENTOMOLOGY 

1919. — Contributions nouvelles a l'etude des formes larvaires des 
nematodes parasites heteroxenes. Bull. Biol. France et Belg. 
(1918), vol. 52, No. 4, Mar. 25, pp. 344-378, figs. I-XIL 

Theiler, (Sir) Arnold. 

1919. — A new nematode in fowls, having a termite as an intermediary 
host. [Filaria gallinarwm (nova species)]. 5. & 6. Rep. 
Director Vet. Research, Dept. Agric. Union South Africa 
(1918), Apr., pp. 695-707, 1 pi., fig. 1. 

Van Saceghem, R. 

1917. — Contribution a l'etude de la dermite granuleuse des equides. 

Bull. Soc. Path. Exot., vol. 10, No. 8, Oct., pp. 726-729. 
1918. — Cause etiologique et traitement de la dermite granuleuse. 
Bull. Soc. Path. Exot., vol. 11, No. 7, July 10, pp. 575-578. 

Villot, Francois Charles Alfred. 

1878. — Migrations et metamorphoses des tenias des musaraignes. 

Ann. Sc. Nat., Zool., vol. 49, 6. s., vol. 8, Nos. 2-3, art. 5, 19 

pp., pi. 11, figs. 1-14. 
1883. — Memoire sur les cystiques des tenias. Ann. Sc. Nat., Zool., 6. s., 

vol. 15, art. 4, Oct., 61 pp., pi. 12, figs. 1-13. 

Von Linstow, Otto Friedrich Bernhard. 

1886. — Ueber den Zwischenwirth von Ascaris lumbricoides L. Zool. 
Anz., No. 231, vol. 9, Aug. 30, pp. 525-528. 

Von Stein, Friedrich. 

1852. — Beitrage zur Entwickelungsgeschichte der Eingeweidewiirmer. 
Zeitschr. f. Wissensch. Zool., vol. 4, No. 2, Sept. 2, pp. 196- 
214, pi. 10, figs. 1-20. 

Wellman, Frederick Creighton. 

1907. — Preliminary note on some bodies found in ticks Ornithodoros 
moubata (Murray) fed on blood containing embryos of Fi- 
laria perstans (Manson). Brit. Med. Journ., No. 2429, vol. 
2, July 20, pp. 142-143. 



CHAPTER VI 

The Relations of Climate and Life and Their Bearings on the Study of 

Medical Entomology. 1 

W, Dwight Pierce 

All animal and plant life has its being and reacts according to defi- 
nite laws in which we find the climatic factor of primary importance. 
We cannot go far into a subject with as many inter-relationships as 
medical entomology without finding it necessary to know something of 
the climatic laws which govern the lives of the various organisms con- 
cerned. 

In several of the lectures attention is especially called to apparent 
discrepancies in the interpretation of climatic effects on the life of the 
insects, and this is particularly true in case of the lice. Throughout 
our literature there is to be found a hazy notion of the importance of 
temperature and still hazier notions of humidity. There is a great' 
deal about these factors which help to govern life, that no one knows, 
but it will pay us to have a clearly defined statement of some of the 
most important principles as now understood. 

On a proper understanding of the relations of temperature and 
humidity to the life and development of insects, animals, and disease 
organisms, depend all transmission experiments, all efforts in keeping 
alive the various creatures involved, all interpretations of results and 
many practical measures of control. 

This difficult subject will be stated in as simple language as possible 
so that all may see the basic principles at least. 

Every one of us knows that cold and heat can cause pain. We have 
indeed a clear understanding that cold and heat kill. We recognize the 
fact that we seem to work best under conditions when we are absolutely 
oblivious of heat or cold, dryness or moisture. We have felt stupid 
in murky weather. We have felt parched and dried from extremely 
dry weather. In other words, we can now recognize four conditions 
which may affect our well-being, cold, heat, dryness, moisture. These 
can be expressed on two scales — temperature and relative humidity. In 
other words, we should be able to chart our own susceptibilities to these 
factors by running, for example, a temperature scale vertically on our 
1 This lecture was read July 1, 1918 and issued the same day. 

97 



98 



SANITARY ENTOMOLOGY 



chart paper and a humidity scale from zero to one hundred per cent 
saturation horizontally. 

If we picture our reactions or those of the creature being studied 
on such a chart (see figs. 8, 9), we will better understand the subject. 
In the lower part of the chart we will locate certain temperatures which 
always cause death from cold. These may be known as ABSOLUTE 
FATAL TEMPERATURES. 

Now a common failing in the past has been to assume that humidity 
had nothing to do with the effect of temperature on life. It does have 
a very decided bearing. A creature which can stand a certain degree 







TEUCeHTAOe MEAN HUMIDITY. 



AN HYPOTHETICAL CHART SHOWING THE ZONES OE LIEE REACTIONS TO 
TEMPERATURE AND RELATIVE HUMIDITY. DIFFERING -TOR EACH SPECIES. 

Fig. 8 

of cold at a given humidity may be absolutely unable to stand that same 
temperature at another degree of saturation or relative humidity. 

Our absolutely fatal temperatures therefore will form some sort of 
a zone on our chart and this zone will probably be bounded by a curve. 
We call the temperatures below this curve the LOWER ZONE OF 
FATAL TEMPERATURES. Death caused by cold is called RHIGO- 
PLEGIA. 

Slightly above these absolutely fatal temperatures will be a zone of 
temperatures which might cause death if experienced sufficiently long, 
but which at least cause a complete suspension of all activity. And 
still higher will be temperatures which also cause suspension of activity, 
but which do not cause death even when experienced for very long pe- 



RELATIONS OF CLIMATE AND LIFE 99 

riods. Formerly, this suspension of activity by animal life on account 
of cold was called hibernation, which means winter rest. The writer has 
shown (Pierce, W. D., 1916, Journ. Agr. Res., vol. 5, pp. 1183-1191) 
that this same inactivity may be caused by dryness or heat and possibly 
by excessive humidity, and that a creature may remain in the same 
state of inactivity from the heat of summer through the cold of winter 
and be awakened from it only by the addition of a requisite amount 
of moisture at effective temperatures. We must seek other terms than 
hibernation, or winter rest, and aestivation, or summer rest. As this 
rest consists essentialhv of an almost complete cessation of all bodily 
functions, and is a state of insensibility, we may very properly designate 
the so-called hibernation as RHIGANESTHESIA, or insensibility due 
to cold. This state may be acquired naturally as winter sets in, or may 
be artificially induced at any time of the year by lowering the tempera- 
ture. The temperatures inducing RHIGANESTHESIA are grouped 
into the LOWER ZONE OF INACTIVITY, or the ZONE OF RHIG- 
ANESTHESIA. 

As the temperatures increase, a creature in the state of rest or 
rhiganesthesia, commences to show slow movements of the body fluids, 
and slight jerky motions, which increase with increase of temperature. 
This awakening or anastasis, when caused by temperature change, is a 
THERMANASTASIS. 

The approximate point at any given humidity at which thermanastasis 
begins is the ZERO OF EFFECTIVE TEMPERATURE. It must be 
firmly fixed in your minds that there is not a single zero of effective 
temperature, as so often claimed, but a different one for every degree or 
portion of a degree of relative humidity. In other words, at one humidity 
the awakening may occur at one temperature, and under other conditions 
of humidity the temperature may be considerably higher or lower. These 
points can be connected by a curve which represents the lower limit of 
the ZONE OF ACTIVITY, or the THERMOPRACTIC ZONE, mean- 
ing a zone of effective temperatures. 

Many authors have manifested considerable confusion in their writ- 
ings and have even claimed that other authors were incorrect because a 
certain developmental period or reaction was accomplished in their ex- 
periments at a given temperature in a certain period of time while the 
other investigators obtained totally different results. A man working 
in a moist coastal section could not justly compare his results with those 
of a man working in a drier section unless the conditions of humidity were 
recorded also. For this reason, the writer has maintained that labora- 
tories attempting to correlate temperature with life history, must at least 
be equipped with maximum and minimum thermometers and a sling 
psychrometer for determining humidity, and that accurate results are 



100 SANITARY ENTOMOLOGY 

based only on a recording hygrothermograph, checked by the above 
mentioned instruments. i 

The great bulk of work naturally is upon the reactions which take 
place in the zone of activity. 

It must not be forgotten, however, that control work depends often 
upon a correct knowledge of the lower zone of fatal temperatures, and 
that successful storage of breeding material, until the investigator is 
ready to use it, depends often upon a knowledge of the requirements of 
rhiganesthesia. 

Following the awakening, the body takes up all its natural functions 
and we must assume that sustenance is available. The first activities, 
at temperatures just above the zero of activity, are naturally very 
sluggish and this state of sluggishness may be known as RHIGO- 
NOCHELIA, or sluggishness caused by cold. 

Some creatures are very sensitive to cold, usually when the humidity 
is high. Pain produced by the application of cold is called CRYAL- 
GESIA. An abnormal sensitiveness to cold is known as CRYESTHESIA, 
and a morbid sensitiveness as HYPERCRYALGESIA. These sensa- 
tions are probably only experienced with a descent of temperatures. 

In the zone of effective temperatures or thermopractic zone there 
is a point or a small restricted zone of temperatures at which all activi- 
ties are most effective, that is, the greatest amount of work is accom- 
plished with the least amount of exertion and the least loss of energy. 
This is the so-called OPTIMUM, or perhaps better, PRACTICOTATUM, 
meaning most effective. As temperatures ascend to the practicotatum 
any given function is performed in proportionately shorter time. As 
the temperatures ascend above the practicotatum a particular function 
may be exercised more rapidly but less accurately or less effectively, as 
for instance, more eggs may be laid but fewer hatch; but the activity is 
feverish and soon exhaustion takes place, or the individual gradually 
becomes more stupid and sluggish. This heat sluggishness is therefore 
called THERMONOCHELIA. 

Different reactions to heat may be experienced and these have all 
received appropriate designations. As for example, a stifling sensation 
is called THERMOPNIGIA ; an unusual sensibility to heat THERMAL- 
GESIA, and a more intense sensibility HYPERTHERMALGESIA. The 
ability to recognize changes of temperature is THERMESTHESIA, 
and its extreme is designated as THERMOHYPERESTHESIA, an 
abnormal sensitiveness to heat stimuli. A fondness for heat or requiring 
great heat for growth is called THERMOPHILIC, while resistance to 
heat is called THERMOPHYLIC. When a stifling temperature is ex- 
perienced rapid breathing or THERMOPOLYPNEA is often experi- 
enced. Contraction under the action of heat is designated as THER- 



RELATIONS OF CLIMATE AND LIFE 101 

MOSYSTALTIC. The adaptation of the body temperature to that of 
the environment is PECILOTHERMAL. A morbid dread of heat is 
THERMOPHOBIA. The determination of the direction or rate of 
locomotion by heat is called THERMOTAXIS and movement brought 
about by heat is THERMOTROPISM. 

As the temperatures increase sluggishness increases until sleep or 
inactivity is induced and this condition once known as aestivation or 
summer rest may better be known as THERMANESTHESIA or insensi- 
bility caused by heat. 

The point at which anesthesia begins at any given tumidity is the 
upper boundary of the thermopractic or effective zone. Those tempera- 
tures at which successful Thermoanesthesia may be experienced embrace 
the UPPER ZONE OF INACTIVITY, or the ZONE OF THERM- 
ANESTHESIA. This quickly merges into those high temperatures which 
may with sufficient duration of time cause death, and finally, those tem- 
peratures which are absolutely fatal under all conditions. The highest 
zone is therefore the UPPER ZONE OF FATAL TEMPERATURES. 
Death from heat is known as THERMOPLEGIA, or heat stroke. 

Most investigators have stopped with a more or less hazy acknowledg- 
ment of the existence of these various zones of reactions on the ascend- 
ing scale of the thermometer, but the literature contains few references 
to similar zones of reactions on the scale of relative humidity, llowever, 
if we stop to think we must acknowledge that similar reactions do take 
place. 

We may have death from absolute dryness at almost any tempera- 
ture, in other words, we have a condition which is called APOXERAE- 
NOSIS, or drying up. At very low humidities one may become insensi- 
ble and thus we have XERANESTHESIA. Likewise, a little higher 
humidity induces sluggishness or a state of XERONOCHELIA. We 
have most of us experienced this condition of stupidity in a living room 
at normal temperatures in the winter due to lack of sufficient moisture. 
So also there is the humidity which enables each individual to accom- 
plish the greatest results in the least time with the least amount of 
exhaustion and this is the PRACTICOTATUM. With increase of 
humidity the activity lessens until an excessively humid atmosphere 
brings about HYGRONOCHELIA or sluggishness due to moisture ; then 
HYGRANESTHESIA may be experienced by some species and finally 
death due to excessive moisture or HYGROPLEGIA. 

This makes it obvious therefore that when we plot the reactions 
of a species to temperature and humidit}', we are likely to find a series 
of closed figures delineating concentric zones of fatal, inactive, active 
and optimum conditions. Thus it is apparent that Rhigoplegia, 
Apoxeraenosis, Thermoplegia, and Hygroplegia form a single zone of 



loa 



SANITARY ENTOMOLOGY 



temperature-humidities which cause death — this whole zone is the fatal 
or OLETHRIC ZONE. All conditions of life lie within it, the next zone 
being that which includes Rhiganesthesia, Xeranesthesia, Thermanes- 
thesia, and Hygranesthesia ; the whole zone therefore being the ANES- 
THETIC ZONE, or zone of rest, which includes the conditions known 
as hibernation and aestivation. Within this is the THERMOPRACTIC 
ZONE or zone of effective temperatures, which is naturally made up of 
sub-zones representing degrees of activity, as the NOCHELIC SUB- 
ZONE of sluggish activities on the outside and the PRACTICOTATUM 
at the center. 



*$$2tM 







SUGGESTED CURVES Of THE RESPONSES OFMRACE AMERICANS TQ f/WKD 
TEMPERATURES WITH CERTAIN AGUAL RECORDS JEWMC ASA BASIS. 

Fig. 9 



Temperature and humidity affect every bodily function of every 
creature of the plant and animal kingdom. Some creatures may love 
cold, some heat, some dryness, some moisture. The pattern of their 
reactions will therefore shift from one place to another on the chart. 
Some creatures may be so resistant to cold that fatal temperatures are 
never normally experienced and rarely artificially. Some may be very 
resistant to dryness and others capable of standing any degree of hu- 
midity. In case of plants the root system receives one set of stimuli 
and the upper portion another, so that the interpretation is not as 
simple as with animals. 

In the different stages of growth a creature may have different abil- 
ity to withstand extremes. 

If the approach to unfavorable or noneffective conditions is gradual, 



RELATIONS OF CLIMATE AND LIFE 103 

the body gradually adjusts and adapts itself for entrance into a dormant 
state. We find adaptations against cold, heat and dryness, often in 
cysts or in cases constructed by the creature, and in fact some of these 
protective cases are made of substances impervious to water. In the 
state of encystment far greater extremes can be experienced than in 
the normal state, because of the impervious nature of the cyst. 

Successful dormancy often depends upon the rapidity with which 
it was brought about. Most creatures practically free the intestinal 
canal before entering a resting stage. 

A sudden lowering or raising of temperature may be fatal at tem- 
peratures which would normally be easily withstood if approached grad- 
ually. 

Alternation of high and low temperatures, if sudden, is often fatal 
at normally effective temperatures. A creature may become dormant 
with descending temperatures at a higher temperature than it would 
awaken with ascending temperatures. 

A continuous maintenance of an even temperature and humidity is 
more or less enervating. A climate which has sufficient variation to 
allow certain periods of rest from cold at night and heat in the day 
is probably productive of better results. It is possible in a given day 
for a creature to have two active and two dormant periods. As for 
example, observations of many insects will show that they sleep during 
the cold parts of a night, are active during the morning, sleep during 
the hottest part of the day, are again active in the evening and early 
parts of the night. It is also noticeable that on humid days many in- 
sects are inactive but as soon as the air dries they again resume activ- 
ity, and the reverse is found in arid regions. 

Many investigators have failed in keeping insects alive for experi- 
ment because of failure to keep sufficient water present for drinking 
purposes and maintenance of proper humidity. 

As long as any creature is experiencing effective temperatures it 
must have food available to take when needed and this food must be in 
proper condition. Long periods without food at noneffective tempera- 
tures can be experienced, but at effective temperatures the length of 
life is relatively short. This is a very important point in control work 
with all insects. If you can deprive them of food for a sufficient period 
when the climatic conditions enforce activity, then control is easy. 

There are many very difficult points in this question. Inasmuch 
as noneffective temperatures and also noneffective humidities may be 
experienced each day, it becomes necessary to make elaborate studies 
to ascertain the boundaries of the thcrmopractic and hygropractic zones, 
and only a thermo-hygrograph record sheet will enable one to make any 
kind of a satisfactory study. 



104* SANITARY ENTOMOLOGY 

There is a rule which receives much support, that a given reaction 
or stage of development is accomplished at an almost constant total 
effective temperature, which is the multiple of time units by temperature 
units accumulated above the zero of effective temperature. Since the 
zero varies with the humidity, the total effective temperature obtained 
by this rule does likewise. We must therefore reword the rule to read: 
A given reaction or stage of development is accomplished at any given 
mean humidity at a constant total effective temperature, which is the 
multiple of effective time units by temperature units accumulated within 
the zone of effective temperatures at a given atmospheric pressure. 
To compute this one must first eliminate all time, temperature, 
and humidity which was noneffective, whether at the top or bottom of the 
scale. For instance, if at 60% humidity the temperatures 65° to 85° 
are effective, and during the day the temperature ranged from 50° to 90°, 
but only during eight hours at the effective temperatures; we must 
multiply the period 8 hours by the mean temperature experienced be- 
tween 65° and 85°, considering 65 as and 85 as 20. The result is 
the total effective temperature of that day. Adding these total effective 
temperatures during the total period of the stage, we obtain the total 
effective temperature necessary to bring about the perfection of the 
stage. Necessarily this is a very complicated proposition, requiring 
very careful computations. Nevertheless, once worked out we can es- 
tablish laws of control which are of utmost vajue. 

Some of the following lectures will refer to the principles laid down 
in this lecture and lines of research will be suggested leading toward 
control measures. The charts (figs. 8, 9) should be studied in connec- 
tion with the lecture. 



CHAPTER VII 

Diseases Borne by Non-Biting Flies 1 
W. Dwight Pierce 

It will be necessary in discussing the role of flies in the transmission 
of disease to divide the flies into several categories, because so many 
species of the order Diptera are involved. The flies can be divided 
into two large groups, those which bite and those which do not bite, 
but, rather, sip their food. Two excellent monographs on the relations 
of flies and disease have been published, that on the non-bloodsuckers by 
Graham-Smith, and that on the bloodsuckers by Hindle. 

This lecture deals with the non-biting flies only. Among these flies 
are to be found the principal house-visiting flies, foremost among which 
is the house or typhoid fly, Musca domestica Linnaeus, followed by the 
blue bottle blow flies, Calliphora vomit oria Linnaeus and C. erythro- 
cephala Meigen, the green bottle blow fly Lucilia caesar Linnaeus, and 
various other species. The mouth parts of these flies are constructed 
only for sucking or sipping liquid or semi-liquid foods. 

In this lecture can only be given a very condensed statement of the 
relationship of these flies to disease. A more extensive study should 
involve the reading of the books by Hewitt and Graham-Smith quoted 
in the bibliography. In these volumes the evidence is given in great 
detail. 

Among the most striking of the investigations into the capacity of 
non-biting flies for the carriage of disease germs, are a series of three 
excellent papers by the Italian investigator, Cao, whose work is over- 
looked by many subsequent writers. In fact, there has been but one 
good review of his results in English. And yet his investigations opened 
up the way for practically all of the work on bacterial transmission by 
insects. Working with larvae and adults of Musca domestica Linnaeus, 
Calliphora vomit oria Linnaeus, Lucilia caesar Linnaeus and Sarcophaga 
carnaria Linnaeus, he proved that the larvae of these flies could take 
up and pass through their intestines any bacteria occurring in their 
food, and that all four species acted exactly alike in this regard. Except 
where he specifically stated, his results applied to all four species in 

J This lecture was presented in two parts on July 8 and 15 and distributed entire 
on July 15, 1918. It has been revised for this edition. 

105 



106 SANITARY ENTOMOLOGY 

every instance. Step by step, he proved that fly-larvae take up bacteria 
from their food, and when breeding in flesh may take up disease germs as 
well as non-pathogenic germs; that these germs may pass unaltered 
through the insects' intestines and out in their feces; that some of them 
may remain for a long period in the intestinal canal, and some even 
may multiply therein; that they may be taken up by the larva and per- 
sist through its metamorphosis until it arrives at the adult stage, and 
for days thereafter, and may be carried by this adult and deposited 
with its feces on food or excrement ; and that these bacteria will also be 
found in the glutmous substances surrounding the eggs when deposited, 
and thus contaminate the substance in which the newly born larvae will 
feed; and of course be taken up by this second generation and possibly 
be distributed farther by it. 

These facts were worked out by Cao in 1905 and 1906, and yet 
Graham-Smith credits Faichnie (who worked in India in 1909) with be- 
ing the first one to suggest that bacteria ingested by the larva might 
survive the pupal stage and be present in the intestine of the adult. 
Later, Bacot, and also Ledingham in 1911 and Graham-Smith in 1912, 
corroborated these claims that the bacteria could persist in the body 
throughout the metamorphosis. 

Ledingham (1911), Nicholls (1912), and Graham-Smith (1912) 
have shown that the fly larvae have great powers of destroying micro- 
organisms due to the fact that many of these organisms are not adapted 
to the conditions prevailing in the interior of the larva and pupa, or 
perhaps more correctly due to the hostile action of bacteria which more 
normally frequent the intestines of the larvae. These normal inhabitants 
of the fly intestine are principally non-lactose fermenting organisms. 

Not only bacteria but also protozoa, such as the amoebae of dysen- 
tery, and the eggs of parasitic worms, may be taken up by the fly larvae or 
adults and deposited in the feces. Roubaud (1918) has brought out 
the fact that multitudes of the amoebic dysentery germs taken up by 
adult flies and deposited in their feces die because of the rapid drying 
of the feces, and he credits the fly with being a great agent in the de- 
struction of multitudes of protozoa, while granting the equally great 
opportunity of the fly to contaminate food therewith. 

Stiles in 1889 fed larvae of Musca domestica with female Ascaris 
lumbricoides, which they devoured, together with the eggs they con- 
tained. The larvae as well as the adult flies contained the eggs of 
Ascaris (Nuttall, 1899, p. 39). Nicoll (1911) has very thoroughly in- 
vestigated the relationships of flies to the possible carriage of eggs of 
worms and demonstrated the ability of adult flies to ingest the eggs of 
various species of worm.*, provided these are small enough, and to pass 



DISEASES BORNE BY NON-BITING FLIES 107 

them out whole in the feces, but in all his experiments with the larvae he 
found that the eggs were crushed. 

In addition to the ability of flies to carry disease germs in their 
body, there are multitudes of proofs of their ability to carry them also 
on their body and to deposit them when they feed. 

The transmission of disease by non-bloodsucking -flies is exclusively 
by contamination either of food, water or wounds. Most of the flies 
which frequent houses and food or visit man because of attractive secre- 
tions or injuries also are attracted to and breed in excreta or garbage. 
Hence the contamination of food by direct transportation from infected 
excreta is a very simple matter. 

This contamination may be by the simple depositing of disease 
germs carried on the body of the flies, or by regurgitation, or the 
deposition of feces. Wherever a fly alights and remains a few minutes 
it deposits either vomit or feces. By the nature of its breeding it is 
hardly to be expected that these deposits will not contain some kind of 
bacteria, and possibly protozoa or worm eggs. If these deposits are 
made on the moist media offered by foods the germs may easily retain 
their virulence until eaten. 

As flies can travel considerable distances, at least thirteen miles, 
the existence of a single disease case with insanitary conditions in the 
vicinity enabling fly breeding, might easily infect an entire city or army 
camp if the flies were permitted to reach the food of the inhabitants. It 
is because of the total lack of sanitary waste disposal in country dis- 
tricts that diseases like typhoid fever and dysentery usually become very 
widespread. We can not know the source of the flies which enter our 
houses. We must not let them visit our food. They must be kept away 
from the eyes and mouths of babies. Our markets where meats and 
vegetables are sold must be better protected. Only through influencing 
public opinion will we be able to have the fly nuisance in our own public 
markets abated. Food offered for sale should be kept under glass or 
screen at all times. 

There are so many organisms transmitted by the non-blood-sucking 
flies that we shall have to deal with them rather briefly and preferably 
according to their classification. A thorough digest of the mass of 
matter submitted below should impress the readers with the necessity 
of fly prevention. 

PLANT ORGANISMS CARRIED BY NON-BITING FLIES 

Thallophyta: Fungi: Schizomycetes: Coccaceae 

Streptococcus equinus Andrewes and Horder, a non-pathogenic organ- 
ism found in horse dung, was found by Torrey (1912) in a number of 
cases on the surface of city caught flies. 



108 SANITARY ENTOMOLOGY 

Streptococcus fecalis Andrewes and Horder, an organism occurring 
normally in the human intestine and occasionally pathogenic has been 
isolated from city caught Musca domestica by Scott (1917), Cox, Lewis 
and Glynn (1912) and Torrey (1912). 

Streptococcus pyogenes Rosenbach, an organism causing ERYSIPE- 
LAS, SUPPURATION and SEPTICAEMIA was isolated by Scott 
(1917) from city caught Musca domestica in Washington. 

Streptococcus salivarius Andrewes and Horder, an organism fre- 
quently found in the mouth, but rarely pathogenic, has been isolated from 
the intestines of city caught Musca domestica by Torrey (1912), and 
was also found on flies by Cox, Lewis and Glynn (1912). 

Diplococcus gonorrhoeae Neisser (Gonococcus), the cause of GONOR- 
RHOEA, was found by Welander (1896) carried on the feet of a fly 
for three hours after they had been soiled with secretion. 

Diplococcus intracellular is meningitidis Weichselbaum {Meningococ- 
cus), the cause of CEREBROSPINAL MENINGITIS, is thought to be 
possibly carried by flies by MacGregor (1917). 

Micrococcus flavus was isolated by Torrey (1912) from the intes- 
tinal content as well as the surface of city caught flies. 

Micrococcus tetragenus Gaffky, commonly found in the human body, 
sometimes pathogenic, sometimes saprophytic, was isolated from Musca 
domestica by Scott (1917). 

Staphylococcus pyogenes alhus Rosenbach, a cause of SEPTICAE- 
MIA, was isolated by Cao (1906B) from the mucilaginous envelope cov- 
ering the eggs of Musca domestica, Sarcophaga vomitoria, Lucilia caesar 
and Calliphora vomitoria at the time of deposition. Scott (1917) iso- 
lated it from the bodies of Musca domestica. 

Staphylococcus pyogenes aureus Rosenbach, a frequent cause of 
ABSCESSES, etc., was shown by Celli (1888) to retain its virulence after 
passing through the flies' intestines. Herms (1915) proved by experi- 
ment that Musca domestica can carry great numbers of this organism 
on its feet. Torrey (1912) and Scott (1917) isolated it from the bodies 
of city caught flies. Cao (1906B) isolated it from the eggs at the time 
of deposition of laboratory caught flies of Musca domestica, Calliphora 
vomitoria, Sarcophaga camaria and Lucilia caesar. 

Staphylococcus pyogenes citreus Passet, a pathogenic, chromogenic, 
pus-forming organism, was isolated by Scott (1917) from bodies of 
house flies Musca domestica in Washington. Cao (1906B) fed larvae of 
Musca domestica, Sarcophaga camaria, Calliphora vomitoria, and 
Lucilia caesar on meat polluted with this organism and recovered it from 
the feces of mature flies bred from these larvae. 

Sarcina aurantiaca Lindner and Koch, a zymogenic, chromogenic 
(orange yellow) organism found in air and water, rarely pathogenic, 



DISEASES BORNE BY NON-BITING FLIES 109 

was found by Cao (1906B) to be capable of passing through the intes- 
tines of larvae of Musca domestica, Calliphora vomitoria, Sarcophaga car- 
naria, and Lucilia caesar, in all stages of larval growth and of remaining 
in the body through pupation to maturity. 

Thallophyta: Fungi: Schizomycetes: Bacteriacece 

Bacillus of Koch- Weeks, the cause of an acute infectious CONJUNC- 
TIVITIS (pink eye), is thought by Castellani and Chalmers (1913, p. 
700) to be frequently carried by the little Oscinid gnat, Microneurum 
funicola Meijere, which causes great annoyance by hovering in front of the 
eyes and attacking the eyes and ears. The flies may be driven away by the 
odor of Odol. 

Bacillus A of Ledingham, a nonlactose fermenter from the feces of 
children, has been found by Tebbutt (1912) to be normal to the house 
fly, Musca domestica, being found on the ova, and in the larvae, pupae and 
adults, and when fed to the larvae survived through the metamorphosis to 
the adult stage. 

Bacillus of Morgan, which is frequently found in cases of INFAN- 
TILE DIARRHEA, has been found in various strains commonly in the 
intestines of Musca domestica by Nicoll (1911), Morgan and Ledingham 
(1909), Cox, Lewis and Glynn (1912) and Graham-Smith (1912), and 
the latter found that when fed to larvae of the house fly it could survive 
through the metamorphosis to the adult fly. 

Bacillus acidi lactici Hueppe, a bacillus common to cows' milk, has 
been isolated from the bodies and from the intestinal contents of Musca 
domestica in New York, Washington, London and Liverpool by Torrey 
(1912), Scott (1917), Nicoll (1911), and Cox, Lewis and Glynn (1912). 

Bacillus aerogenes capsulatus Welch and Nuttall is a pathogenic 
organism gaining entrance to the body chiefly through wounds and caus- 
ing severe infections resulting often in GANGRENE. In the surgery 
of the Great War this organism has been a very important one. It 
occurs as a normal inhabitant of the intestine of man and some of the 
animals. It has been isolated by Torrey (1912) from the surface as 
well as the intestinal contents of city caught flies. 

Bacterium anthracis Davaine, the cause of ANTHRAX, although 
probably more often carried by biting flies, has been shown by Davaine 
(1870) to be capable of carriage by Calliphora vomitoria. He fed flies 
on anthracic blood and inoculated guinea pigs with parts of these flies 
40 hours to 3 days later, obtaining fatal results in 4 out of 7 cases. 
From flies of Calliphora vomit oria caught in his laboratory Cao (1906B) 
isolated virulent germs of B. anthracis adhering to the glutinous secretion 
surrounding the eggs as they were deposited. He later placed on flesh 



110 SANITARY ENTOMOLOGY 

of animals dead from anthrax externally sterilized eggs of Musca 
domestica, Calliphora vomitoria, Lucilia ccesar and Sarcophaga carnaria 
and from day to day dissected the larva; feeding on this flesh, always 
demonstrating anthrax germs in their bodies, and he further proved 
that these larvae retained the germs in their bodies through pupation to 
maturity and for at least nine days after maturity. He fed flies on 
meat polluted with anthrax and demonstrated twenty-four hours later 
the bacilli in the feces and on the eggs. Graham-Smith (1912) found 
that many blow flies (Calliphora erythrocephala and Lucilia cazsar) 
which emerged from larvae fed on meat infected with anthrax spores were 
infected and remained so for 15 da} T s or more. He also found that a large 
proportion of house flies (Musca domestica) which develop from larvae 
fed on spores of B. anthracis are infected. Because of the habit of blow 
flies of breeding in and attacking wounds there have been many cases 
of human anthrax on the battle front in Europe. The ease with which 
this may occur is quite evident in view of the above quoted investigations. 

Bacillus cloacte Jordan has been found in the alimentary canal of 
Musca domestica in London by Nicoll (1911). 

Bacillus coli Escherich, an organism normally found in the alimentary 
canal of man, but often found causing secondary infections, was found 
by Cao (1906B) in various strains adhering to the eggs at the time of 
oviposition of flies caught in the laboratory (Musca domestica, Sarco- 
phaga carnaria, Lucilia coesar, and Calliphora vomit oria). 

Bacillus coli anaerogenes was isolated by Scott (1917) from Musca 
domestica caught in Washington. 

Bacillus coli communior Dunham, an abundant inhabitant of the 
human and animal intestine, has been isolated from the body and intes- 
tinal contents of Musca domestica in New York and Washington by 
Torrey (1912) and Scott (1917). 

Bacillus coli communis Escherich, an organism common in the intes- 
tine of man and animals and associated with a large variety of lesions, 
has been isolated from the body and intestinal contents of Musca 
domestica by Torrey (1912), Nicoll (1911), Scott (1917) and Cox, 
Lewis and Glynn (1912). 

Bacillus coli mutabilis was found on the body and in the intestines 
of Musca domestica in London by Nicoll (1911). 

Bacillus " colisimile" Cao was fed by Cao (1906B) to larvae of Musca 
domestica, Calliphora vomitoria, Lucilia cwsar and Sarcophaga carnaria 
in flesh and he later demonstrated its abundant presence in the feces of 
the larvae. 

Bacillus cuniculicida Koch and Gaffky, the cause of SEPTICAEMIA 
in rabbits and guinea pigs, was isolated by Scott (1917) from house flies 
(Musca domestica) caught in Washington, and he looks upon the fly 



DISEASES BORNE BY NON-BITING FLIES 111 

as the carrier of laboratory epidemics of rabbit and guinea pig septicaemia 
experienced for several years. 

Bacillus diphtheric! Klebs, the cause of DIPHTHERIA, according to 
experiments performed by Graham-Smith (1910) may be taken up by flies 
feeding on infected saliva or sputum and may live in the crop and intes- 
tines of the fly for over 21 hours, and in fact in one experiment he twice 
recovered it from the feces of flies 51 hours after feeding on bacilli emulsi- 
fied in broth. 

Bacillus dy sentence "T" Hiss and Russell, one of the organisms found 
in DYSENTERY and INFANTILE DYSENTERIC DIARRHEA, was 
experimented with by Tebbutt (1913) who fed it with blood to larvae of 
Musca domestica. The eggs from which these larva? were hatched were 
washed in weak carbolic acid or lysol to disinfect them. Before feeding 
the larvae on the organism they were carefully washed in weak lysol 
solution. In a limited number of cases the bacillus was recovered from 
the pupa? and adults of larvae thus fed. 

The Shiga bacillus, Flexner bacillus and parabacillus of dysentery 
were all isolated on flies in Macedonia and a decided correlation between 
the incidence of flies and dysentery was established by Col. Dudgeon 
(1919) and associates. They found the examination of fly feces the 
most suitable method for the isolation of dysentery bacilli. 

Bacillus enteritidis Gaertner, the cause of FOOD POISONING in 
man, and epizootic diseases among animals, was experimented with by 
Graham-Smith (1912), who fed it to the larvae of Calliphora erythro- 
cephala and Musca domestica, but did not recover it in the adults matured 
from these larvae. Cox, Lewis and Glynn (1912) isolated a similar 
bacillus from flies caught in Liverpool. 

Bacillus fecalis alkaligenes Petruschky, a not infrequent inhabitant 
of the human intestine, which has been associated with a case of severe 
gastroenteritis, was isolated by Torrey (1912) from the intestinal con- 
tent of city caught flies in two different instances. 

Bacillus ftuorescens liquefaciens Fluegge, a common organism found 
in water and air, was fed by Cao (1906B) to larvae of Musca domestica, 
Calliphora vomitoria. Lucilia ccesar, and Sarcophaga carnaria, on flesh 
containing the organisms, and found among the predominant bacteria in 
the feces of the larvae. He found that this organism taken up by the 
larvae could persist through the pupal stage and be obtained from the 
feces of flies immediately after their emergence, and when fed to adults 
it was demonstrated on their eggs when deposited. 

Bacillus jluorescens nonliquefackns Eisenberg and Krueger, found in 
water and in butter, was fed by Cao (1906B) to larva 1 of Musca 
domestica, Calliphora vomitoria, Lucilia civsar, and Sarcophaga carnaria. 
and later demonstrated in the feces of the larvae. 



112 SANITARY ENTOMOLOGY 

Bacillus gasoformans nonliquefaciens was found on the body and in 
the alimentary canal of Musca domestica caught in London by Nicoll 
(1911). 

Bacillus grilnthal was found on the body and in the intestines of 
Musca domestica by Nicoll (1911). 

Bacillus lactis acidi Marpmann, a zymogenic bacillus found in cows' 
milk, was isolated by Torrey (1912) from the surface of city caught flies. 

Bacillus lactis aero genes Escherich, which is almost constantly found 
in milk and is one of the chief causes of souring of milk, was isolated from 
flies by Cox, Lewis and Glynn (1912). 

Bacillus lepra? Hanson, cause of LEPROSY, may be carried by Musca 
domestica, according to Leboeuf (1913). 

Bacillus mallei Loffler and Shutz may be transmitted by flies according 
to Rosenau (1916). 

Bacillus neapolitanus has been found on the body of Musca domestica 
by Nicoll (1911) and Cox, Lewis and Glynn (1912). 

Bacillus oxytocus perniciosus Wyssokowitsch, a pathogenic organism 
found in milk, has been isolated from the intestines of Musca domestica 
by Nicoll (1911). 

Bacillus paracoli Duval and Schorer, a pathogenic organism found 
frequently in the stools of children suffering from summer diarrhea, has 
been isolated several times by Torrey (1912) in New York, both from 
the surface and intestines of city caught flies. 

Bacillus paratyphosus "A" Schottmiiller, cause of PARATYPHOID 
A fever was isolated from the intestinal contents of city caught flies by 
Torrey (1912). 

Bacillus paratyphosus "B" Schottmiiller, cause of PARATYPHOID 
B fever, was recovered from the body and intestines of Musca domestica 
caught in London by Nicoll (1911), with the evidence that it had been 
carried by the flies at least for 11 days. 

Bacillus pestis Kitasato, the cause of BUBONIC PLAGUE, although 
normally carried by fleas, has been shown by Yersin (1894) and Nuttall 
(1897) capable of remaining in the intestines of flies in a virulent condi- 
tion for at least 48 hours after infection. Nuttall's experiments indicated 
that this bacillus is fatal to Musca domestica. 

Bacillus prodigiosus Ehrenberg, a nonpathogenic, zymogenic, and 
chromogenic organism, was fed by Cao (1906B) to adult flies of Musca 
domestica, Calliphora vomitoria, Lucilia caisar, and Sarcophaga carnaria 
and was demonstrated in their feces and on their eggs 24 hours later. 
Larvae fed on polluted meat contained the germs in their bodies and 
carried them through pupation and they could be demonstrated in the 
intestines of the adult up to nine days after emergence. Ledingham 
(1911) corroborated Cao's findings of the persistance of this bacillus 



DISEASES BORNE BY NON-BITING FLIES 113 

throughout the metamorphosis of Musca domestica. Graham-Smith 
(1913) found that flies of Musca domestica fed on this bacillus may infect 
milk for several days, while Calliphora vomitoria flies when infected con- 
stantly produced infection in milk up to the eighth day and in syrup up 
to the twenty-ninth day. 

Bacillus proteus vulgaris Hauser, B. p. mirabilis Hauser, and B. p. 
zenkeri were fed by Cao (1906B) to larvae of Musca domestica, Calliphora 
vomitoria, Sarcophaga carnaria, and Lucilia coesar, and were found 
abundantly in the feces of the larvae so fed. Species of Proteus were also 
found deposited with the eggs of flies fed on infected flesh. Bacillus 
proteus vulgaris was isolated by Scott (1917) from Musca domestica 
caught in Washington. 

Bacillus pyocyaneus Gessard associated with SUPPURATING 
WOUNDS in which blue-green pus is present was isolated in two strains 
from flies caught in Liverpool by Cox, Lewis and Glynn (1912). Bacot 
and Ledingham (1911) by carefully controlled experiments have proved 
that the larvae of Musca domestica fed on infected food retain this bacillus 
in the gut through the metamorphosis to the adult stage and may dis- 
tribute it in their excreta. 

Bacillus radiciformis Tataroff, a saprophytic organism found in 
water, was fed by Cao (1906B) to larvae of Musca domestica, Calliphora 
vomitoria, Lucilia ccesar and Sarcophaga carnaria, and recovered from 
the feces of the larvae. 

Bacillus ruber kielensis Breunig, a chromoparous (red) bacillus found 
in water at Kiel, was fed by Cao (1906B) to larvae of Musca domestica, 
Sarcophaga carnaria, Calliphora vomitoria, and Lucilia c&sar, and he 
demonstrated that the larvae could take it up in all stages of growth, and 
that the bacilli persisted in their bodies through pupation to maturity. 

Bacillus schafferi Freudenreich, a nonpathogenic, zymogenic organism, 
found in "puffy" and "Nissler" cheese, has been found by Nicoll (1911) in 
London on the body and in the intestines of Musca domestica. 

Bacillus septicus agrigenus Nicolaier, a pathogenic organism, was fed 
by Marpmann (1897) to flies, and 12 hours later the contents of the 
flies were inoculated into mice, producing fatal infection in a large per 
cent of the inoculations (Nuttall 1899). 

Bacillus " simile arbonchio" Cao, a pathogenic organism similar to 
Bacillus anthracis, which produces CARBUNCLES when inoculated, was 
fed by Cao (1906B) to larvae of Musca domestica, Calliphora vomitoria, 
Lucilia coesar and Sarcophaga carnaria and isolated from the feces of 
the larvae in a very virulent strain. In examinations of many flies caught 
in the laboratory he occasionally isolated a non-pathogenic, mobile strain 
of this organism. 

Bacillus subtilis Ehrenberg, an organism frequently found in air, 



114 SANITARY ENTOMOLOGY 

water, and soil, and seldom pathogenic, was fed by Cao (1906B) to larva? 
of Musca domestica, Calliphora vomitoria, Lucilia cwsar and Sarcophaga 
carnaria and was among the predominant bacteria recovered from the 
feces of the larva?. 

Bacillus suipestifer Salmon and Smith, often found in cases of FOOD 
POISONING and SUMMER DIARRHEA, is recorded by Scott (1917) 
from the house fly, Musca domestica. 

Bacillus "tifo simile" Cao, a pathogenic organism strongly resembling 
B. typhosus, was fed by Cao (1906B) to larvae of Musca domestica, 
Calliphora vomitoria, Lucilia cazsar, and Sarcophaga carnaria and later 
demonstrated in the feces of the larva? as among the predominant forms in 
strains of differing virulence. From flies caught around the laboratory 
he isolated pathogenic strains adhering to the eggs when deposited. 

Bacillus tuberculosis Koch, the cause of TUBERCULOSIS, was found 
in four out of six flies caught by Hofmann (1888) in the room of a tuber- 
culosis patient, whose sputum had contained many germs. Flies fed 
artificially with sputum died in a few days. Within twenty-four hours of 
their being fed on the sputum, the tubercle bacilli appeared in their 
excreta. A guinea pig inoculated with the intestines of flies developed 
tuberculosis. Celli (1888) reports Alessi's experiments of inoculating 
the feces of flies fed on tubercular sputum, and causing the development 
of tuberculosis in two rabbits. Spillman and Haushalter (1887) were, 
however, the first to find the tubercle bacilli in the intestines and feces of 
flies which had fed on sputum. 

Bacterium tularense McCoy and Chapin, cause of a fatal RODENT 
PLAGUE of which a few human cases are on record, may be transmitted 
by Musca domestica. Wayson (1915) inoculated the crushed bodies of 
flies fed on the viscera of an animal dead 48 hours and obtained fatal 
results in three series of experiments with guinea pigs. 

Bacillus typhosus Eberth, the cause of TYPHOID FEVER, was 
first shown by Celli (1888) to be capable of passing through the intestines 
and into the feces of flies. Many authors have added proofs of the role 
of the fly in the transmission of this disease and these are ably summarized 
by Graham-Smith (1913) and Hewitt (1914). Faichnie (i909) proved 
that flies could carry this bacillus in their intestines for 16 days. Leding- 
ham has isolated the bacillus from the intestines of Musca domestica which 
had fed on it in the larval stage, but found that the normal bacilli in the 
larval intestines usually prevent its successful survival through meta- 
morphosis. 

Bacillus vesiculosus, which is very frequently found in human excre- 
ment, was found on the body of Musca domestica caught in London by 
Nicoll (1911). 

Bacillus xerosis Kutschert and Neisser, a presumably nonpathogenic 



DISEASES BORNE BY NON-BITING FLIES 115 

organism, usually found in the eyes, and often associated with conjunc- 
tivitis, was isolated by Torrey (1912) on the surface of city caught flies. 

Thallophyta: Fungi: Schizomycetes: Spirillaceae 

Spirillum (Vibrio) cliolerce Koch, the cause of ASIATIC CHOLERA, 
may be carried by flies. The connection of flies with the prevalence of 
cholera was first noted by Nicholas (1873). Maddox (1885) first per- 
formed experiments with Calliphora vomit oria Linnaeus and Eristalis 
tenacc Linnaeus as well as other insects and determined microscopically 
the presence of the motile cholera vibrios in the feces. Tizzoni and 
Cattoni (1886) caught flies in cholera wards and after several hours 
obtained characteristic cultures of the organism. Many other authors, as 
Sawtchenko (1892), Simmonds (1892), Uffelmann (1892), Macrae 
(1894), have furnished proofs of fly dissemination of the cholera vibrio, a 
summary of which can be found in the books by Graham-Smith and 
Hewitt. 

SUMMARY OF PLANT ORGANISMS 

A brief survey of the data presented above will perhaps help to imprint 
the gravity of the fly menace on all who read this. Sixty-three minute 
plant organisms have been shown to be transmissible by domestic flies. 
Forty-four of these organisms have been found on or in flies caught in 
cities or buildings, in other words, were naturally carried by so-called 
"wild flies." Among these forty-four organisms naturally carried by flies 
were several normal inhabitants of milk, also various normal inhabitants 
of the human and of animal intestines, which could only be taken up from 
excrement. Some of these organisms are taken from eyes, some from 
sputum, some from decaying vegetable matter, others from dairy products. 
The fly containing such organisms betrays its habits. We find the 
organisms of conjunctivitis, infantile diarrhea, sour milk, gas gangrene, 
enteritis, guinea pig septicaemia, leprosy, paratyphoid A, and paraty- 
phoid B fevers, bubonic plague, green pus, food poisoning, tuberculosis, 
typhoid fever, anthrax, rodent plague, gonorrhea, abscesses, erysipelas, 
bacillary dysentery, and cholera, and possibly cerebrospinal meningitis, 
normally carried by flies which frequent our houses, visit our bodies and 
pollute our food with their excreta. We also find experimental evidence 
that these same flies can carry the organisms of diphtheria, gastroenter- 
itis, and other pathogenic conditions. 

In other words, it would seem that non-blood-sucking flies can carry 
any bacterial or coccal disease in which the organism may be reached by 
the fly on the body of the person, in his sputum, or his excreta, and 
undoubtedlv the same is true of such diseases of animals. 



116 SANITARY ENTOMOLOGY 

It is of interest to note that in nineteen species the organism has been 
proven to pass freely through the intestinal canal of the larvae, in thirty- 
seven species through the intestines of the adult, and in eleven species 
to be capable of persisting in the larvae through metamorphosis to the 
adult. What greater argument could be found that flies are dangerous 
not only because of what they as flies have fed on, but also because of 
food they took while larvae, possibly a long distance away? 

We have not, however, gauged the depth of the fly's infamy, as we have 
so far only listed the evidence of plant diseases transmitted. 



DISEASES OF UNSETTLED ORIGIN PROBABLY CAUSED BY 
MICROORGANISMS 

PURULENT OPHTHALMIA is said to be carried by flies in Egypt. 
Brumpt accused Musca domestica of being a carrier of TRACHOMA. 
Rosenau stated that flies have been found breeding in open lesions of 
SMALLPOX, and that flies may transmit MEASLES and SCARLET 
FEVER. Definite experiments certainly should be carried out with a 
view to determining the exact relationship of flies to these diseases, seek- 
ing first the possibility of transmission by fecal contamination. 

Howard and Clark (1912) found that Musca domestica flies can 
retain the virus of INFANTILE PARALYSIS or POLIOMYELITIS 
either in or on their bodies for 24 and 48 hours. The virus may remain 
alive in the body of the fly six hours after ingestion. The fly can obtain 
the virus from secretions of nose and throat and discharge of intestines. 

Very recently Dorset (1919) and associates have experimentally 
transmitted HOG CHOLERA by inoculating with crushed bodies of 
infected Musca domestica and Fannia canicularis, and also by bringing 
such flies in contact with abraded surfaces. 



ANIMAL ORGANISMS CARRIED BY NON-BITING FLIES 

We will now consider in a similar manner the evidence of transmission 
of animal organisms by these same flies. 

Protozoa 

Sarcodina: Amoebvna: Amoebidae 

Loschia coli (Losch) (Endamoeba) a supposedly harmless commensal 
in the alimentary canal of man, where it feeds on the contents of the 
bowels, may be carried in the encysted form by Musca domestica, accord- 









DISEASES BORNE BY NON-BITING FLIES 117 

ing to Roubaud (1918), who finds that the cysts readily pass through the 
fly intestines at laboratory temperatures of 15-18° C. (59-65° F.) in 24 
hours. It may be carried from jhfected stools to food but must be 
deposited in moist substances, as all cysts dry rapidly in dry fly 
feces. 

Loschia histolytica (Schaudinn), the cause of AMOEBIC DYSEN- 
TERY, may be carried in the encysted form by Musca domestiea and 
Calliphora erythrocephela according to Flu (1916). Roubaud (1918) 
has carefully investigated and finds that the free amoeba is quickly 
digested by the fly, but the cysts may pass readily through the intestines 
within 24 hours and may be demonstrated up to 40 hours. The cysts die 
rapidly in dry fly feces, and therefore to live must be placed on moist 
substances, or on food. 

Mastigoplwra: Protomonadina: Bodonidae 
Prowazehia sp. is found in Fannia canicularis (Dunkerly 1912). 

Mastigophora: P olymastigina : Polymastigidae 

Giardia intestinalis (Lambl) (Lamblia), the cause of LAMBLIAN 
DYSENTERY of rodents and man, may be carried in the encysted form 
by Musca domestiea, according to Roubaud (1918), but must be deposited 
in the feces on moist substances, or directly on food. 

Mastigophora: Binucleata: Leptomonidae 

Crithidia calliphorae Swellengrebel is described as a parasite of 
Calliphora erythrocephala Meigen. 

Crithidia muscae-domesticae Werner is described as a parasite of 
Musca domestiea Linnaeus. 

Leptomonas calliphorae (Swingle) is a parasite of Calliphora erythro- 
cephala Meigen. 

Leptomonas drosophilae Chatton and Alilaire is a parasite of 
Drosophila confusa. 

Leptomonas homalomyiae (Brug) is a parasite of Fannia scalajis 
Fabricius. 

Leptomonas lineata (Swingle) is a parasite of Sarcophaga sarraceniae 
Riley. 

Leptomonas luciliae (Strickland) is a parasite of Lucilia sp. 

Leptomonas luciliae (Roubaud) is described as a parasite of Lucilia 
serenissima Walker. 

Leptomonas mesnili Roubaud is a parasite of Lucilia sp. 



118 SANITARY ENTOMOLOGY 

Leptomonas muscae-domesticae (Burnett) is a parasite of Musca 
domestica Linnaeus, M. nebulo Fabricius, Fannia scalaris Fabricius, 
Pollenia rudis Robineau-Desvoidy, Teichomyza fusca Macquart, Lucilia 
sp., Pycnosoma putorium Wiedemann, Scatophaga lutaria Fabricius, 
Neuroctena anilis Fallen, Homalomyia comma Verrall, and Sarcophaga 
murus, undergoing complete metamorphosis in the bodies of the flies. 
Patton (1910) has demonstrated that the disease may be transmitted 
from fly to fly as follows : the food becomes infected from the feces of 
the infected flies which have fed on it ; uninfected flies may become in- 
fected by ingesting either the long flagellates, the short encysting forms, 
or the cysts, in the feces of other flies, or in food contaminated by other 
flies. 

Leptomonas pycnosomae Roubaud is a parasite of Pycnosoma 
putorium. 

Leptomonas roubaudi Chatton is a parasite in the Malpighian glands 
of Drosophila confusa Staeger. 

Leptomonas sarcophagae (Prowazek) is a parasite in the gut of 
Sarcophaga haemorrhoidalis Fuller and another species of Sarcoph- 



Leptomonas soudanensis Roubaud is a parasite of Pycnosoma 
putorium. 

Leptomonas stratiomyiae (Fantham and Porter) is a parasite of 
Stratiomyia chameleon Linnaeus and S. potamida Meigen. Fantham and 
Porter (1916) proved it experimentally pathogenic by inoculation to 
Mus mus cuius. 

Leishmania tropica (Wright), the cause of ORIENTAL SORE of 
man, may be taken up in the crithidial stage by Musca domestica and 
the organism demonstrated 48 hours after feeding, according to Carter 
(1909). According to Wenyon (1911) who investigated BAGDAD 
SORE, Musca domestica may readily feed on the sores and take up 
Leishmania, but there is no development of the organism and no parasites 
were found in the feces. On the other hand, Row, working with CAMBAY 
SORE believed the organism transmissible by Musca domestica up to 
three hours after the fly had fed on infected sores. He found the gut con- 
tents of flies infective for a monkey three hours after the fly had taken up 
Leishmania, but Patton (1912) maintains that Cambay sore never com- 
mences in a cut, scratch or abrasion, and failed to transmit the disease 
in this manner in numerous experiments with Musca nebulo and Musca sp. 
A new investigation, however, is warranted by Row's statement, seeking 
fecal infection of wounds. 

Rhynchoidomonas luciliae Patton is parasitic in the Malpighian 
tubules of Musca nebulo and Lucilia serenissima. 



DISEASES BORNE BY NON-BITING FLIES 119 



Mastigophora: Binucleata: Trypanosomidae 

Castellanella evansi (Steel) Chalmers (Trypanosoma) 2 , the cause of 
SURRA, an African disease of horses and other mammals, may be carried 
by Musca domestica by contact with wounds. 

Castellanella hippicum (Darling) Chalmers (Trypanosoma), 2 the 
cause of MURRINA, a disease of horses and mules in the United States 
and Panama, may be carried according to Darling (1911, 1912) by Musca 
domestica, Chrysomya and Sarcophaga, from wounds by mechanical 
transmission. He ascertained that the trypanosomes remained alive in 
the proboscis of the fly at least two hours, and he also successfully inocu- 
lated a mouse with the crushed portions of a proboscis of a fly which had 
fed on infected blood. Isolation of the animals from fly attack, and bind- 
ing up of wounds wiped out the epidemic. He did not ascertain whether 
the trypanosome might pass out of the fly's feces and contaminate lesions 
in this manner, which naturally is the normal method of fly transmission. 



Mastigophora: Spirochaetacea: Spirochaetidae 

Treponema pertenue (Castellani), the cause of YAWS, an infectious, 
disease of men, may be transmitted by the house fly, Musca domestica. 
Castellani in Ceylon (1907) found that flies eagerly crowd around the 
open sores of yaws patients. In the hospitals as soon as the dressings 
were removed from the yaws ulcerations, they became covered with flies, 
sucking with avidity the secretion, which they may afterward deposit in 
the same way on ordinary ulcers on other people. He conducted experi- 
ments which proved that the flies do take up the organism, which he recov- 
ered from the dissected mouth parts. He fed flies on the organism, then 
removed their appendages and fastened them over scarified areas of skin 
of monkeys, and obtained in two experiments positive lesions by this 
organism. Robertson (1908) also definitely obtained this spirochaete 
from flies collected on yaws lesions. Nicholls (1912) ascribes most of the 
cases of yaws in the West Indies to inoculation of surface injuries by 
Oscinis pallipes Loew. Sarcophaga is also considered a carrier. None 
of the experiments have been directed at obtaining infection through the 
deposition of the spirochaetes, taken up by the fly in feeding, in its feces 
on other ulcers or injuries. This would appear to be the most likely 
method of infection. 

2 The classification of the Trypanosomes has recently been modified by Chalmers, 
including several genera composed of species with similar morphological and bio- 
logical characteristics. 



120 SANITARY ENTOMOLOGY 

Neosporidia: Myxosporidia: Nosemidce 

Nosema apis Zander, a bee disease, may be communicated to Calliphora 
vomit oria and other insects through feeding on the bee excreta around 
beehives. 

Protozoa: Neosporidia: Myxosporidia: Thelohanidae 

Octosporea monospora Chatton and Krempf is a parasite of Farmia 
scalaris. 

Thelohania ovata Dunkerly is also a parasite of Fannia scalaris. 

HIGHER ORGANISMS CARRIED BY FLIES 

As pointed out in the introduction of this lecture, flies can carry the 
eggs of higher organisms. The evidence is presented below, but refer- 
ence should be made to Dr. Ransom's lecture (Chapter V). 

Platyhelmia: Cestoidea: Cyclophyllidea: Taeniidae 

Taenia (Taeniarhynchus) saginata Goeze, the FAT-TAPEWORM 
of cattle and rarely of man, has been commonly found in the egg stage in 
Musca domestica in British East Africa according to Shircore (1916). 
It is necessary that the eggs, passed in human or animal feces, reach the 
food or water of the next host (cattle). This may occur by means of 
insanitary sewage disposal, possibly under exceptional circumstances by 
the agency of flies. 

Platyhelmia: Cestoidea: Cyclophyllidea: Hymenolepididae 

Choanotaenia infumdibulum (Bloch) Cohn, the FOWL TAPEWORM, 
developed to the cysticercoid stage in Musca domestica fed on the eggs, 
and Guberlet (1916) succeeded in infecting new-born chicks by feeding 
them on infected Musca domestica. 

Davamea cesticillus Molin, a fowl tapeworm, was tested with negative 
results by Guberlet (1916), using Musca domestica and Calliphora vomi- 
toria in his search for the intermediate host. 

Davainea tetragona Molin, another chicken tapeworm, likewise gave 
Guberlet (1916) negative results with the same two species of flies. 

Platyhelmia: Trematoda: Malacotylea: Schistosomidae 

Schistosoma mansoni Sambon, the trematode worm causing intestinal 
Schistomiasis of man or BILHARZIOSIS, may be found in the egg stage 



DISEASES BORNE BY NON-BITING FLIES 121 

in Musca domestica, according to Shircore (1916), who recorded eggs of 
this species in flies in British East Africa. The cercaria stage is passed 
in a snail. 

Nemathelminthes : Nematoda : Spiruridae 

Habronema muscae (Carter) Diesing, a STOMACH WORM OF 
HORSES, passes its earlier stages in Musca domestica, according to Ran- 
som (1913). Either the egg or first-stage larva is ingested by the fly 
larva breeding in horse manure. Development goes on within the fly 
larva and pupa, the last stage being found in the proboscis of the adult 
fly. It passes to horses through the swallowing of infested flies and 
probably may also leave the proboscis of the fly while the insect is feeding 
on the mucous membranes of the horse. 

Van Saceghem (1917, 1918) placed flies bred from larva? fed on 
infected manure, on skin lesions of a horse and produced infections of 
EQUINE GRANULAR DERMATITIS, caused by the presence of 
Habronema larvae in the skin. 

Habronema microstoma (Schneider) Ransom and H. megastoma 
(Rudolphi) Seurat have also been shown to pass their developmental 
stages in Musca domestica. (See Chapter V.) 



Nemathelminthes : Nematoda: Ascaridae 

Ascaris lumbricoides Linnaeus, the cause of HUMAN ASCARIASIS, 
does not require an intermediate host. Stiles in 1889 fed Musca domestica 
larvae on female Ascaris and later found the eggs in different stages of 
development in both larvae and adult flies (Graham-Smith, 1913). Shir- 
core (1916) in British East Africa found the eggs in the intestines of 
Musca domestica in nature. Nicholls (1912) in St. Lucia found the 
eggs in the abdomens of flies, Borborus pumctipennis Macquart (Limo- 
sina) 9 taken at fecal matter. (See Chapter V.) 



Nemathelminthes : Nematoda: Oxyuridae 

Oxyuris Curvula Rudolphi, the EQUINE PINWORM, is recorded 
by Patton and Cragg (1913), as probably the species of Oxyuris, which 
in Madras is often found in the embryo stage heavily infesting the larvae 
of Musca nebulo. 

Oxyuris vermicularis Linnaeus, the HUMAN PINWORM, can be 
ingested in the egg stage by flies, according to Grassi (1883). 



122 SANITARY ENTOMOLOGY 

Nemathelminthes: Nematode, : Ancylostomidae 

Ancylostoma duodenale Dubini, cause of HOOK WORM disease of 
man, has been found in the egg stage in house flies, Muse a domestica, by 
Shircore (1916) in British East Africa, and it is therefore possible that 
the eggs may be placed on food, in which the hook worm larva could 
hatch and be directly conveyed into the body with the food. No develop- 
ment takes place in the flies. 

Necator americanus Stiles, the American HOOK WORM, was collected 
in the egg stage in the intestines of Limosina punctipennis in St. Lucia 
by Nicholls (1912). Galli-Valerio (1905) found that flies could carry 
on the surface of their bodies not only the eggs but also the larvae 
of this worm. 

Nemathelminthes : Nematoda: Trichosomidae 

Trichiuris trichiura (Linnaeus), the WHIP WORM of man, was col- 
lected in the egg stage by Shircore (1916) in British East Africa in the 
abdomen of Musca domestica and by Nicholls (1912) in St. Lucia in the 
abdomen of Borborus punctipennis (Limosina) , and the latter succeeded 
in feeding Musca domestica on the eggs. It probably does not require 
the flies as immediate hosts, but is undoubtedly distributed in this manner. 

Thus to the already long list of serious diseases in whose spread the 
non-blood-sucking flies may play some part we may now add hog cholera, 
poliomyelitis, amoebic dysentery, Lamblian dysentery, Oriental sore, 
surra, murrina, yaws, purulent ophthalmia, trachoma, the fat-tapeworm 
of cattle, the fowl tapeworm, bilharziosis of man, the stomach worm 
of horses, equine granular dermatitis, human ascariasis (not normal 
method), equine pinworm, pin itch, two hook worms, and the whip worm, 
and possibly also smallpox, measles and scarlet fever. 

We found that the bacteria were only mechanically carried by the 
flies, except in the case of Bacillus anthracis. Among the protozoa also 
those organisms parasitic in vertebrates all seem to be mechanically 
transmitted. The various parasites mentioned, however, pass complete 
life cycles in the body of the fly. Among the worms, however, there are 
cases of external mechanical carriage, transmission of eggs through 
the intestinal canal, retention of the egg from larva to adult fly (Ascaris 
lumbricoides), and also cases of the fly serving as an intermediate host 
(Choanotaenia infundibulum, and Habronema spp.). The last named 
worms are the only organisms known to be transmitted by the fly which 
work forward into the proboscis for transmission at time of feeding. 

A bibliography of the works cited in the lecture follows : 



DISEASES BORNE BY NON-BITING FLIES 123 

IMPORTANT GENERAL TEXTBOOKS 

Fantham, H. B., Stephens, J. W. W., and Theobald, F. V., 1916.— The 

Animal Parasites of Man. Wm. Wood & Co., New York, 900 pp. 

Graham- Smith, G. S., 1913. — Flies in Relation to Disease. Non-Blood- 
Sucking Flies. Cambridge Univ. Press, 292 pp. 

Herms, Wm. B., 1915. — Medical and Veterinary Entomology. The Mac- 
millan Company, New York. 

Hewitt, C. Gordon, 1914. — The House Fly, Musca domestic a Linn. Its 
Structure, Habits, Development, Relation to Disease and Control. 
Cambridge Univ. Press, 382 pp. 

Hindle, Edward, 1914. — Flies in Relation to Disease. Blood-Sucking 
Flies. Cambridge Univ. Press, 398 pp. 

Patton, Walter Scott, and Cragg, Francis William, 1913. — A Textbook 
of Medical Entomology. Christian Literature Society for India, Lon- 
don, Madras and Calcutta, 764 pp. v 

Riley, W. A., and Johannsen, O. A., 1915. — Handbook of Medical 
Entomology. Comstock Publishing Company, Ithaca, N. Y. 

SPECIAL REFERENCES 

Cao, G., 1898.— L'Ufficiale San. Riv. DTgiene di Med. Patr., vol. 11, pp. 

337-348, 385-397. 
Cao, G., 1906A.— Annali DTgiene Sper., vol. 16, n. s., pp. 339-368. 
Cao, G., 1906B. — Annali D'Igiene Sper., vol. 16, n. s., pp. 645-664. 
Carter, R. M., 1909.— Brit. Med. Journ., vol. 2, pp. 647-650. 
Castellani, A., 1907. — Journ. Hygiene, vol. 7, p. 567. 

Castellani, A., and Chalmers, A. J., 1913. — Manual of Tropical Medi- 
cine, 2nd edit., p. 700. 
Celli, A., 1888. — Bullet, d. Soc. Lancisiana d. Ospedali di Roma, fasc. 1, 

p. 1. 
Cox, G. L., Lewis, F. C, and Glynn, E. E., 1912. — Journ. Hygiene, 

vol. 12, No. 3, pp. 306-309. 
Darling, S. T., 1911. — Journ. Infect. Diseases, vol. 8, No. 4, pp. 467- 

485. 
Darling, S. T., 1911.— Parasitology, vol. 4, No. 2, pp. 83-86. 
Darling, S. T., 1912.— Journ. Exper. Med., vol. 15, No. 4, pp. 365- 

366. 
Darling, S. T., 1912. — Trans. 15th Internat. Congress Hyg. and Demog., 

Washington. 
Davaine, C, 1870.— Bullet, de l'Acad. de Med., Paris, vol. 35, pp. 471- 






124 SANITARY ENTOMOLOGY 

Dorset, M., McBryde, C. N., Nile, W. B., and Rietz, I. H., 1919.— Amer. 

Journ. Vet. Med., vol. 14, No. 2, pp. 55-60. 
Dudgeon, L. S., 1919.— Brit. Med. Journ., No. 3041, April 12, pp. 448- 

451. 
Dunkerly, J. S., 1912.— Central, f. Bakt., Paras, und Infekt., vol. 62, 

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Faichnie, N., 1909. — Journ. Royal Army Med. Corps, vol. 13, pp. 580- 

584, 672-675. 
Fantham, H. B., and Porter, A., 1916. — Journ. Parasit., vol. 2, No. 4, 

pp. 149-166. 
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and Medical Subjects, n. s., No. 40, pp. 1-40. 
Graham-Smith, G. S., 1912.— Forty-first Ann. Rept. Local Govt. Bd. 

1911-12, Suppl. Rept. Medic. Off., pp. 304-329, 330-335. 
Grassi, B., 1883.— Arch. Ital. de Biol., vol. 4, pp. 205-208. 
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237. 
Hofmann, E., 1888. — Correspondenzbl. d. arztl. Kreis- und Bezirks- 

vereine im Kbnigr. Sachsen, vol. 44, No. 12, pp. 130-133. 
Howard, C. W., and Clark, P. F., 1912.— Journ. Exper. Med., vol. 16, 

No. 6, pp. 850-859. 
Leboeuf, A., 1913.— Bull. Soc. Path. Exot., vol. 6, No. 8, pp. 551-556. 
Ledingham, J. C. G., 1911. — Journ. Hygiene, vol. 11, No. 3, pp. 333- 

340. 
MacGregor, M. E., 1917. — Journ. Trop. Med. and Hygiene, vol. 20. No. 

18, p. 207. 
Macrae, R., 1894.— Indian Med. Gazette, pp. 407-412. 
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607, 941-952. 
Marpmann, G., 1897.— Centralbl. f. Bakteriol., 1 Abt., vol. 22, pp. 127- 

132. 
Morgan, H. deR., and Ledingham, J. C. G.> 1909. — Proc. Roy. Soc. 

Med., vol. 2, pt. 2, pp. 133-149. 
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Nicholls, L., 1912.— Bull. Ent. Research, vol. 3, No. 1, p. 85. 
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Patton, W. S., 1910.— Bull. Soc. Path. Exot., vol. 3, pp. 264-274. 



DISEASES BORNE BY NON-BITING FLIES 125 

Patton, W. S., 1912.— Sci. Mem. Officers Med. & Sanit. Dept., Govt. 

India, No. 50, 21 pp. 
Ransom, B. H., 1913.— U. S. Dept. Agr., Bur. Anim. Ind., bull. 163, 

pp. 1-36. 
Robertson, A., 1908. — Journ. Trop. Med. and Hygiene, vol. 11, p. 

213. 
Rosenau, M. J., 1916. — Preventive Medicine and Hygiene, pp. 206-252. 
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171. 
Sawtchenko, J. G., 1892. — Review in Ann. Inst. Pasteur, vol. 7. 
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Shircore, J. O., 1916.— Parasitology, vol. 8, No. 3, pp. 239-243 
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Berlin, pp. 769-771. 
Torrey, J. C, 1912.— Journ. Infect. Diseases, vol. 10, No. 2, pp. 169- 

176. 
Uffelmann, J., 1892.— Berliner klin. Wochenschr., pp. 1213-1214. 
Van Saceghem, R., 1917.— Bull. Soc. Path. Exot., vol. 10, p. 726; 1918, 

vol. 11, p. 575. 
Wayson, N. E., 1915.— U. S. Public Health Service, Pub. Health Repts,, 

vol. 29, No. 51, pp. 3390-3393. 
Welander, 1896. — Wien. klin. Wochenschr., No. 52. 
Wenyon, C. M., 1911.— Kala Azar Bull., vol. 1, No. 1, pp. 36-58. 
Yersin, A., 1894.— Ann. Inst. Pasteur, vol. 8, pp. 662-667. 



CHAPTER VIII 

Important Phases in the Life History of the Non-Biting Flies * 
W. Dwight Pierce 

In the preceding lecture there was brought together an accumulation 
of evidence against the common flies that frequent our houses which 
should convince any one of the absolute necessity of keeping flies from 
our food, our houses and our bodies. We can only hope to accomplish 
this object by becoming familiar at least with the more important features 
in the life history of the flies. From the study of the transmission of 
diseases we may pick out for example a few points in the biology which 
need to be stressed, such as feeding habits, regurgitation of food, excreta, 
breeding places, oviposition, flight, attraction to odor. 

We are dealing in this lecture not only with the common house fly 
but also with most of the common flies which frequent our houses and are 
known as domestic flies. Of the common household flies, only one, the bit- 
ing stable fly, Stomoocys calcitrans, is omitted for future discussion. 

Students would do well to examine some book in which the different 
species are illustrated, so as to become familiar with the characteristic 
markings. It will then be a good plan to collect the various flies around 
the house and determine their species. 

Fairly good illustrations of common household flies are given by 
Howard and Hutchinson (1915), and Richardson (1917). 

The best illustrations of the flies are contained in Patton and Cragg's 
textbook (1913). 

Tables to species of common flies and also illustrations are presented 
by Riley and Johannsen (1915). 

It is also desirable to know how to identify the fly larvae when found. 
The best American work on this subject is by Banks (1912). See also 
Riley and Johannsen, p. 315. 

For general information on the life history, morphology, and anatomy 
of the house fly refer to Hewitt (1917). 

The flies are classified largely on the characters of the proboscis, 
antenna, wing veins, eyes and the arrangement of hairs. The larvae are 
classified on the characters of the spiracles, the cephalo-pharyngeal 
skeleton, tubercles, hairs and processes. 

1 This lecture was read July 22 and distributed July 29, 1918. 

126 



PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 127 

HOUSE FLY, MUSCA DOMESTICA LINNAEUS 2 

(See Frontispiece) 

The common house fly, Mwsca domestica, is that insect charged with 
the carriage of the greatest number of diseases, and probably justly, be- 
cause of its frequentation of all types of excreta, garbage and waste, 
its common visitations to places where foods are handled, and also its 
visits to the human body. We have shown in the preceding lecture how 
it and its allies can carry disease and what diseases are charged against 
each. Now we will take a brief review of its life history in order to 
arrive at important data for handling its control. 

The house fly adult is yellowish to dark gray in color, with four 
equally broad longitudinal stripes on the thorax; first three abdominal 
segments yellowish with a central black stripe and with two less distinct 
discal stripes. The males measure 5.8 to 6.5 mm. in length, and the 
females 6.5 to 7.5 mm. The eyes in the male are nearly contiguous and 
in the female are widely separated. 

This fly has been distributed by commerce to almost all parts of the 
civilized world. 

Certain features of its anatomy are of interest in the present study. 

The head is prolonged to form a proboscis which is enlarged at tip 
into the haustellum bearing apically the oral lobes or labella. These lobes 
bear a large number of channels kept open by incomplete chitinous rings 
called pseudotracheae, which are fully described by Graham-Smith (1913). 
The proboscis of the house fly is adapted to sucking and the absorption 
of liquid or liquefied food. It cannot take up very large particles of solid 
food. Nicoll (1911) found that the flies could not ingest particles larger 
than .045 mm. This therefore determines the size of worm eggs which 
can be ingested by the adult. We must assume . therefore that when 
flies contain larger eggs, these were taken in by the larva. Normally, 
however, the food must pass between the bifid extremities of the chitinous 
rings of the pseudotracheal channels and pass along these to the mouth. 
These openings measure from .003 to .004 mm. in diameter. Solid par- 
ticles, however, are heaped up in a slight ridge in the channel between the 
oral lobes and are probabty sucked into the oral pit and into the 
mouth. 

When the fly feeds on dry substances such as sugar, dried specks of 
milk, or sputum, etc., it first liquefies the substance by a salivary secre- 
tion which flows into the oral pit and onto the substance, being dis- 
tributed by the pseudotracheal channels. The moistening is also aided 

2 An appeal has been made to the International Commission for Zoological Nomen- 
clature for the retention of Musca in this sense with domestica as type. 



128 SANITARY ENTOMOLOGY 

by the regurgitation of food from the crop, as proven by Graham-Smith, 
who fed flies upon carmine colored food, and found carmine stains on 
semi-fluid material upon which these flies later fed, for 22 hours. 

The intestinal canal is composed of pharynx, esophagus, crop, pro- 
ventriculus, ventriculus or chyle stomach, proximal and distal intestine 
and rectum. The esophagus passes from the pharynx through the cer- 
vical region into the thorax, in the anterior part of which it opens into 
the proventriculus, and from this same point a duct which is continuous 
with the esophagus passes back into the abdomen to the crop which is a 
bilobed sac, capable of considerable distention. This crop serves as a 
food reservoir. The fly feeds until it has engorged the crop, and often 
will continue feeding, the food then passing directly into the proventri- 
culus. The opening of the proventriculus into the esophagus is ventral. 
This organ is circular, flattened dorsoventrally. The ventriculus is 
tubular, narrowest in front and narrowing again in passing through the 
thoraco-abdominal foramen. The proximal intestine is the longest region 
of the gut, being considerably coiled. The distal intestine begins at the 
entrance of the Malpighian tubules, and is only curved once. It is sep- 
arated from the rectum by a valve. The rectum is composed of three 
parts, the intermediate of which is swollen to form the rectal cavity into 
which the four rectal glands empty. 

Food may remain in the crop for several days, and even when no 
further food is given, it requires many hours to empty the crop com- 
pletely. After feeding the fly usually retires to a quiet spot and cleans 
its head and proboscis. It frequently regurgitates its food from the crop 
in the form of large drops of liquid which are subsequently slowly drawn 
up again and probably pass into the proventriculus. These drops of 
regurgitated food frequently are deposited, often for the purpose of 
moistening sugar and similar dry foods. 

We may now see how easy it is for a fly which has fed on infected 
substances to contaminate other substances for days by regurgitation 
from the crop, as well as through fecal deposits. Experimental evidence 
has proven contamination by both the feces and the vomit. 

The fly's body is externally constructed so as to further aid in 
disease carriage. There are numerous hairs or setae on the body, espe- 
cially on the legs. The last joint of the tarsus of each leg bears two 
claws and a pair of membranous pyriform pads or pulvilli. These pulvilli 
are covered beneath with innumerable, closely set, secreting hairs by means 
of which the fly is able to walk in any position on highly polished sur- 
faces. These sucker-like pads or pulvilli and the setae of the legs are 
excellent bacteria carriers, and not infrequently larger organisms as 
mites, worm eggs, etc., are thus carried. 

The sexes of the house fly are about equal in number. Copulation 



PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 129 

may take place, according to Hutchison (1916), as early as the day 
following emergence. Oviposition may begin on the third day. 

He cites a large series of observations on the preoviposition period 
showing that eggs may be laid from 2Vo to 23 days after emergence, and 
that the period corresponds to temperature and humidity changes. At 
Washington the shortest period was obtained at 82° to 84° F., and in 
general the length of period increased with the decrease of temperature. 
Increase in humidity seems to hasten egg laying. 

The eggs are white, cylindrically oval, slightly broader at the pos- 
terior end with two distinct curved rib-like thickenings on the dorsal 
surface, along one of which the egg splits on hatching. These eggs 
are laid in masses averaging about 120, and a female may lay as many 
as four such batches, and probably under favorable conditions more. The 
eggs usually hatch in less than 24 hours, the time of course depending 
upon the climatic conditions. At 10° C. (40° F.) the egg period is two 
or three days; at 15 to 20° C. (59-68° F.) it is 24 hours; at 25-35° C. 
(77-95° F.) only 8 to 12 hours, according to Hewitt (1917). 

The larvae are white, smooth, cylindrical maggots, tapering at the head 
end and considerably enlarged at the tail end. When viewed by trans- 
mitted light a dark chitinous structure can be seen in the anterior 
regions. This is called the cephalopharyngeal skeleton and is partially 
extrusible. Each species of fly larva is distinguished by the form of this 
skeleton and hence if a slide mount is made of a skin boiled in potash, the 
species can be identified by this and one or more other characters. The 
three larval stages differ somewhat in the form of this skeleton so that it 
becomes possible to determine exactly the stage of development. The 
body is composed of fourteen segments of which the second is the pro- 
thorax. This segment at its posterior margin bears the anterior spiracles 
which are fan-shaped and have six or seven lobes. This segment is fol- 
lowed by the mesothorax, metathorax, and eight abdominal segments. 
The ninth and tenth (anal) segments are small and ventral. The 
anterior portion of the venter of each of the first eight abdominal 
segments bears spiniferous pads which assist in locomotion. The eighth 
or last apparent segment bears the spiracular plates. These spiracular 
plates afford the best means of identification of fly larvae. In the first 
two stages each plate consists merely of two oblique slits on a slight 
prominence. In the third stage they are well defined plates, D-shaped, 
closer together than their width, with flat faces opposed, each with three 
sinuous slits. 

In connection with this larval description, we may call attention to 
errors existing in many larval descriptions. The thoracic spiracles belong 
to mesothorax but often appear to have migrated to the prothorax. The 
large terminal spiracles of Dipterous larvae are always on the eighth 



130 SANITARY ENTOMOLOGY 

segment, as in almost all orders of insects. The ninth and tenth seg- 
ments are apt to be small and obscure and center around the anus, which 
belongs to the tenth. 

The larval period varies in response to climatic stimuli, but under 
favorable conditions is about four days in length. When full grown the 
larva varies from 10 to IS mm. in length. Pupation takes place within 
the last larval skin which shrinks and hardens to form a reddish case or 
puparium. This period lasts from 3 to 10 days. When the fly is ready 
to emerge it pushes off the cap or head end. The entire developmental 
period may require from eight to eighteen or more days. Kisliuk has 
found pupae of the fly in manure piles at various times during the win- 
ter, which of course indicates that the developmental period may occupy 
an entire winter if the pupa is caught by cold weather. Bishopp, Dove 
and Parman found that adults emerged from immature stages which had 
been in manure for six months. Hutchison's observations at Washington, 
D. C, confirm these findings. 

The adult flies are capable of considerable flight. Parker demon- 
strated a migration of two miles in his Montana studies. Bishopp and 
Laake (1919) record the flight of marked house flies of thirteen miles. 
In this connection the most interesting contribution is that of Ball 
(1918) in which he shows that house flies apparently migrated with the 
wind from 46 to 95 miles from mainland to a tiny island. 

The house fly has been found breeding in horse manure, human excre- 
ment, and hog manure very freely and to some extent in cow and chicken 
manure. It lays its eggs in a great variety of decaying animal and 
vegetable materials, such as slops, spent hops, moist bran, ensilage, 
rotting potatoes, dead animals, excreta-soiled straw, paunch contents of 
slaughtered animals, soiled paper and rags, etc. 



The large blue bottle fly, CallipJiora vomit oria Linnaeus (plate I, 
fig. 1) and its near relative C. erythrocephala Meigen are often found in 
houses. These flies have also been shown to be dangerous insects because 
of their ability to transmit disease. In fact they are much more likely 
to directly transmit disease organisms than the house fly because of 
their habits of breeding in flesh which gives them also the name blow flies. 
The adults are grayish on the thorax and dark metallic blue with sug- 
gestions of silver on the abdomen. In vomitoria the genae are black and 
beset with golden red hairs, while in erythrocephala the genae are fulvous 
to golden yellow and beset with black hairs. 

3 An appeal has been made to the International Commission for Zoological Nomen- 
clature for the retention of CallipJiora in this sense with vomitoria as type. 



PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 131 

These flies are necrophagous and deposit their eggs upon any fresh, 
decaying or cooked meat, and upon dead insects ; they breed occasionally 
in human excrement and sometimes will deposit their eggs in open flesh 
wounds. On the battle fronts of Europe and Asia where the wounded lay 
for long periods and where many dead bodies remained uncared for, these 
flies multiplied to tremendous numbers and were largely responsible for 
the carrying of infections to wounds. When a fly lays its eggs in living 
flesh and the larvae develop therein, the infection is called myiasis. This 
subject is of such importance that two entire lectures is devoted to it 
(Chapters XII and XIII). 

Important as they are, the blow flies are usually subordinated to 
the house fly in the discussion of dangerous flies, but thorough investi- 
gations of these species are more than likely to greatly increase their 
standing as disease carriers. 

The eggs are deposited in masses of as many as 300 and a single 
fly may possibly deposit three batches. They hatch in from 10 to 24 
hours after deposition. 

The larvae of C. erytlirocepliala may be distinguished from the house 
fly larvae by having usually nine but sometimes up to twelve lobes in the 
anterior (thoracic) spiracles; an anterior scabrous swollen ring on each 
of the first eight segments of the abdomen, and a ventral groove on 
each segment beneath; the stigmal field concave, surrounded by three 
pair of tubercles above, and two large and one small pair below; the 
stigmal plates about once and a fourth their diameter apart, each with 
three straight slits, directed principally toward the opposite plate ; and 
also, by having an anal pair of tubercles. The larval characters are 
illustrated by Hewitt and also by Banks. 

The larval period requires seven and a half to eight days at 23° C. 
(73.5° F.) and the pupal period fourteen days, according to Hewitt. 
Bishopp and Laake found the larvae to attain full growth in three to four 
days and the time from deposition of eggs to emergence of adults was 15 
to 20 days. 

THE SHEEP MAGGOTS OR GEEEX BOTTLE FLIES 

The European sheep maggot fly, Lucilia sericata Meigen, is primarily 
an outdoor fly but occasionally is found indoors, especially in farm and 
country houses. It is more brilliant than the Calliphoras, being of a 
burnished gold with a shining, bluish-green color. The flies are strongly 
attracted to meat and carcasses in which they lay their eggs. They 
also occur on human and animal excrement. The larvae breed readily 
in all these substances. In Europe the flies very commonly lay their 
eggs in matted wool and on the flesh on the backs of sheep, and the larvae 



132 SANITARY ENTOMOLOGY 

breed in the flesh causing external myiasis. This species attacks ulcers 
and sores of men and animals. Its most common attack on sheep and 
calves is made on the soiled rumps of animals suffering from diarrhea. 
No doubt the flies also serve as distributors of the diarrhea. 

The larva has eight-lobed anterior spiracles. The same number of 
tubercles margin the stigmal plate behind as in Calliphora, but they are 
smaller and sharper. The stigmal plates are about one-half their 
diameter apart, each with three straight slits, directed somewhat toward 
each other, but also downward. 

Undoubtedly under battle front conditions this fly can be expected 
to visit human wounds and breed in them even more readily than Cal- 
liphora. It has been shown by Cao to transmit anthrax with equal 
ease. 

Several other species of Lucilia have like habits, and the larvae of 
two of these, L. caesar Linnaeus (not sericata Meigen), and L. sylvarum 
Meigen have been described and illustrated by Banks. 

The larvae of L. caesar measure 10 to 11 mm. in length and" have not 
adequately been separated from Calliphora erythrocephala. The larval 
period averages about fourteen days and the pupal stage about the 
same. Bishopp and Laake state that in Texas, during warm weather, 
the larval period ranges from three to twelve days, the pupal stage five 
to sixteen days and the total developmental period eleven to twenty-four 
days. This fly is illustrated in plate I, Fig. 2. 

OTHER SCREW WORMS AND BLOW FLIES 

The question of myiasis, which covers screw worms and blow flies, is to 
be considered in separate lectures (Chapters XII and XIII), but mention 
must be made of them at present because undoubtedly many infectious 
diseases are carried by these insects which attack alike live flesh through 
wounds, and dead animals. I would hardly hesitate to claim that 
probably all such flies may carry anthrax at least, and probably do carry 
other diseases. 

Bishopp, Mitchell, and Parman (1917) describe quite fully the habits 
of the common American screw worm, Chrysomya macellaria Linnaeus 4 
(plate I, fig. 3, plate II) which breeds in both Carcasses and flesh wounds 
(plate IV). They also treat the black blow fly Phormia regina Meigen 
(plate I, fig. 4), and other species. The large hairy blow fly, Cynomyia 
cadaverina, Robineau-Desvoidy, and the gray flesh flies Sarcophaga 
texana Aldrich, S. tuberosa var. sarracenioides Aldrich, S. sarraceniae 

4 An' appeal has been made to the International Commission on Zoological Nomen- 
clature to retain Chrysomya in the sense with macellaria as type. 



PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 133 




Plate I. — Screw worms and blow flies. Fig. 1 (upper left). — The blue bottle fly, Cal- 
liphora vomitoria. Fig. 2 (upper right). — The green bottle fly, LucUia caesar. Fig. 
3 (lower left). — The American screw worm, Chrysomya macellaria. Fig. 4 (lower 
right). — The black blow fly, Phormia regina. (Howard and Pierce, photos by 
Dovener.) 



134 



SANITARY ENTOMOLOGY 




Plate II. — Eggs of the American screw worm, Chrysomya macellaria, on meat. 
(Bishopp.) 



PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 135 

Riley (plate III, fig. 1) and S. robust a Aldrich are also among the most 
common flesh flies. 

Froggatt (1915) has given a very fine treatment of the most impor- 
tant sheep maggot flies and has presented colored illustrations of some 
of them. 

All of these flies are likely to be found in houses and markets and 
when given the opportunity will lay eggs on meat offered for sale or 
exposed in kitchens or mess halls. If this meat is already cooked there is 
a good chance of the eggs being ingested and giving rise to gastrointestinal 
myiasis. But the danger from flesh flies is greater than the mere 
causation of external or internal myiasis. The flies which lay the eggs 
may have bred in diseased carcasses, and if so, probably will deposit with 
the eggs a glutinous film containing bacteria from these carcasses, for it 
will be remembered that the fly larva takes up these bacteria and they 
may remain in its body until it as a mature fly lays its eggs, and even 
longer. It must be borne in mind that because conditions in the imme- 
diate vicinity are sanitary, does not mean that the flies which come 
are sanitary, because Bishopp and Laake (1919) record the flight of 
marked Chrysomya macellaria flies for 15 miles, and of Phormia regina 
for 11 miles. 

OTHER EXCREMENT BREEDERS 

Others of our house flies, as the non-biting stable fly, Muscina 
stabulans Macquart (plate III, fig. 2), the lesser house fly Fannia cani- 
cularis Linnaeus (plate III, fig. 3), and the latrine fly F. scalaris 
Fabricius breed in decaying vegetables and animal matter. 

Muscina stabulans looks very much like the house fly, but it is a 
little more robust. It is gray and the thorax is marked with four 
longitudinal black lines. Parts of the legs and scutellum are reddish. 
The principal differential character is in the wing venation. The larva, 
however, is easily distinguished from Muse a domestica, by the six-lobed 
anterior spiracles and the anal stigmal plates scarcely elevated, less 
than their diameter apart, each with three very short slits pointing 
towards those of the opposite plate. It breeds in decaying and live vege- 
table matter, human and animal excreta, and has even been reared from 
insect puparia. It breeds likewise in raw and cooked meats and on car- 
casses. It is therefore a very potential disease carrier, possessing all 
the opportunities of the house fly, with which it may already be mixed 
in medical literature. 

Fannia canicularis and F. scalaris are two flies commonly found in 
houses, which greatly resemble the house fly, but the former may be dis- 
tinguished by the presence of only three dark stripes on the thorax 
instead of the four found in the house fly. The larva. 3 of these flies are very 



136 



SANITARY ENTOMOLOGY 




Plate III. — Flies with dangerous habits. Fig. 1 (upper left). — A flesh fly, Sarcophaga 
sarraceniae. Fig. 2 (upper right). — The non-biting stable fly, Muscina stabulans. 
Fig. 3 (lower left). — The lesser house fly, Fannia canicularis. Fig. 4 (lower 
right). — The brilliant green fly, Pseudopyrellia cornicina. (Howard and Pierce, 
photos by Dovener.) 



PHASES IN THE LIFE HISTORY OF NON-BITING FLIES 137 

readily separated by the large number of processes on all the seg- 
ments. The posterior spiracles are located on raised processes and are 
not plates as in the species mentioned above. In F. canicularis there 
are four lobes to the posterior spiracles and six finger-like lobes to the 
anterior spiracles (see Hewitt, 1917) (see figs. 14 to 19). 

These flies breed in excrement, and in all kinds of decaying vegetable 
matter and are often found in cases of intestinal myiasis. 



REFERENCES 

Ball, S. C, 1918. — Migration of Insects to Rebecca Shoals Light Station 
and the Tortugas Islands, with Special Reference to Mosquitoes and 
Flies. Carnegie Inst., Washington, Publ. 252. 

Banks, Nathan, 1912. — The Structure of Certain Dipterous Larvae with 
Particular Reference to Those in Human Foods. 

Bishopp, F. C, 1915. — Flies Which Cause Myiasis in Man and Animals. 
Some Aspects of the Problem. Journ. Econ. Ent., vol. 8, pp. 317- 
329. 

Bishopp, F. C, and Laake, E. W., 1919. — The Dispersion of Flies by 
Flight. (Abstract) Journ. Econ. Ent., vol. 12, pp. 210-211. 

Bishopp, F. C, Mitchell, J. D., and Parman, D. C, 1917.— U. S. Dept. 
Agr., Farmers' Bull. 857. 

Froggatt, W. W., 1915. — Sheep Maggot Flies. Dept. Agr., New South 
Wales, Farmers' Bull. 95. 

Graham-Smith, G. S., 1913. — Flies in Relation to Disease. Non-blood- 
sucking Flies. Cambridge Univ. Press. 

Hewitt, C. G., 1917.— The House Fly. Cambridge Univ. Press. 

Howard, L. O., and Hutchison, R. H., 1915. — House Flies, U. S. Dept. 
Agr., Farmers' Bull. 679. 

Hutchison, R. H., 1916.— U. S. Dept. Agr. Bull. 345. 

Nicoll, W., 1911.— Journ. Hygiene, vol. 11, No. 3, pp. 381-389. 

Parker, R. R., 1916. — Dispersion of Musca domestica under City Condi- 
tions in Montana. Journ. Econ. Ent., vol. 9, pp. 325-351. 

Patton, W. S., and Cragg, F. W., 1913.— A Textbook of Medical En- 
tomology. 

Richardson, C. H., 1917. — The Domestic Flies of New Jersey. New Jer- 
sey Agric. Exp. Sta., Bull. 307. 

Riley, W. A., and Johannsen, O. A., 1915. — Handbook of Medical 
Entomology. 






CHAPTER IX 

Common Flies and How to Tell Them Apart x 
C. T. Greene 

Only a few of the very common flies have been included in this chap- 
ter; the flies that are likely to appear near any house or in any camp. 
All of them may be attracted by the odors of fresh and cooking foods. 
In the following pages are presented two tables, one to separate the dif- 
ferent species of the adult flies, and the other to separate the different 
larvae or maggots of the flies. All the terms for the different parts of 
the flies and maggots have been made as plain as possible so that the 





sSc/c/or/a/ /y/>e. 3/h'nj type. 
Mouth Parts. 

Fig. 10.— Mouth parts of flies: a, Suctorial type; b, biting type. (Greene.) 

tables can be used by a non-entomologist. In the first table for the adult 
flies is given the style of the -mouth-parts (see fig. 10), that is, whether 
they are adapted for biting or are simply suctorial, then the common 
name is given, and then the scientific name. In the second table the larvae 
or maggots can be separated into different species. Under the name of 
each species, the larva or maggot is described in further detail and here 
mention is made as to where the species will breed. 

1 This lecture was presented September 9, and issued September 11, 1918. It has 
been somewhat modified. 

138 



COMMON FLIES AND HOW TO TELL THEM APART 139 

All the Sarcophagid or "flesh flies" can be readily separated from all 
the other flies in the following table because their bodies are entirely 
gray. The head is rather a bright red, the top of the back has three 
parallel dark stripes and the top of the abdomen has lighter reflecting 
areas, giving it somewhat of a checkered appearance. 



TABLE TO SEPARATE THE ADULT FLIES 

Grayish flies with from two to four longitudinal stripes more or less 
indicated on the thorax. 

1. Dark gray, medium sized fly; top of thorax with four parallel, 
black stripes; sides of abdomen with a large yellow area (variable 
in size and never definitely outlined) ; mouth-parts of the suc- 
torial type (see fig. 10a), never for biting; variable in size but 

Head 

■ THOZAX 




"/iBDOMZN 



MuSC A DOMEJT/C* L 

Fig. 11. — Diagrammatic sketch of the house fly, Musca domestica. (Greene.) 

average about one-quarter inch in length. The common house fly 
(Frontispiece, figs. 11, 12a) also called typhoid fly. 

Musca domestica Linnaeus. 

2. Brownish-gray fly, slightly larger and broader than the house fly. 
Top of thorax with two long, parallel, black stripes and on each 
side of these is a large black dot, below which is a black stripe 
about half as long as the two long stripes. Abdomen with two 
or three cone-shaped dark brown spots in the center and two or 
three round spots on each side (fig. 12c). Mouth-parts piercing 
or biting type (fig. 10b). Stable fly, also called biting house fly 
(fig. 46). Stomoxys calcitrans Linnaeus. 

3. Very dark gray fly, smaller and more slender than the house fly. 
Abdomen pointed and more conical in shape. Yellow spots on the 
sides definitely outlined (fig. 12b). Mouth-parts are of the suc- 
torial type (fig. 10a). The small house fly (plate III, fig. 3). 

Fannia canicular is Linnaeus. 

4. Gray fly, a little larger than the house fly. (About the size of 
Stomoxys calcitrans.) Top of thorax has two short, black 



140 SANITARY ENTOMOLOGY 

stripes. Joints of legs reddish at base. Abdomen is gray and 
in certain lights there are paler gray areas which look like 
spots but there are never any definitely outlined spots. Mouth- 
parts suctorial type (fig. 10a). Another stable fly (plate III, 
fig. £). Muscina stabulans Linnaeus. 

II. Bluish, or greenish flies. 

1. Large blue fly, with grayish thorax (average length three-eighths 
to seven-sixteenths of an inch). This fly is rather broad and 
robust and in certain lights the abdomen shows paler, reflecting 
areas but not definite spots. Mouth-parts suctorial type (fig. 
10a). The common blow fly. Lower part of head (cheeks) red- 
dish and the beard black. Calliphora erythrocephala Meigen. 

2. A slightly larger fly than the preceding but more shiny and a 
deep greenish blue. Abdomen slightly more pointed and of an 






Muse* Domestical Fanni/i cawculax/s. L. Jtomoxyj calcitraNS. 

Fig. 12. — Abdominal markings of three common house flies: a, the house fly, Musca 
domestica; b, little house fly, Fannia canicularis ; c, stable fly, Stomoxys calcitrant. 
(Greene.) In these diagrams the relative size of the abdomen is shown. The 
light areas in a and b represent yellow markings and are variable in size. In fig. 
c the markings of the last segment may be present or absent. 

even coloration (no reflecting spots). Mouth-parts suctorial type 
(fig. 10a). Lower part of head black and the beard red. An- 
other blow-fly (plate I, fig. 1). Calliphora vomit oria Linnaeus. 

3. Much smaller fly, shiny green with a decided whitish bloom on 
the thorax and abdomen. Mouth-parts suctorial (fig. 10a). A 
green bottle fly. Lucilia sericata Meigen. 

4. A slightly smaller fly, shiny, metallic green with a decided bluish 
tinge and no white bloom. Mouth-parts suctorial (fig. 10a). 
Green bottle fly (plate I, fig. £). Lucilia caesar Linnaeus. 

5. A dark green fly, little larger than the above species. It is shiny 
with bluish tinge. Top of thorax with three dark longitudinal 
stripes. Thorax often has a bronze tinge. (Average length five- 
sixteenths to three-eighths of an inch.) Mouth-parts of the suc- 
torial type (fig. 10a). The "screw-worm fly" (plate I, fig. 3). 

Chrysomya macellaria Fabricius. 



COMMON FLIES AND HOW TO TELL THEM APART 141 

6. Deep, shiny blue fly often with a blackish tinge (about five-six- 
teenths of an inch in length). Mouth-parts of the suctorial type 
(fig. 10a). The black blow fly (plate I, fig. 4). 

Phormia regina Meigen. 

III. Ashen gray to deep gray flies. Top of thorax with three blackish, 
longitudinal stripes. The abdomen has lighter gray reflecting 
spots (in certain lights). The different species vary in size 
from a small fly up to a half inch in length. Mouth-parts are 
of the suctorial type (fig. 10a). Flesh flies (plate III, fig. 1). 

Sarcophagidae, 

THE LARVAE OR MAGGOTS 

There is a considerable number of flies whose larvae or maggots 
either regularly or occasionally live in substances used by man as food. 
The great majority pass through the intestinal tract without our 
knowledge, for most of them cause little or no trouble. Many dipterous 
larvae occur in decaying fruits and vegetables and on fresh and cooked 
meats. The blow fly, for example, will deposit on meats in a pantry; 
while other maggots occur in cheese, etc. Pies and puddings in restau- 
rants are often accessible and very suitable places for flies to deposit 
their eggs and no doubt a great many maggots are swallowed in this 
way. The occurrence of dipterous larvae in man is known as "myiasis." 
Various names or divisions are given, as "myiasis externa" or "myiasis 
dermatosa" for larvae in the skin or wounds ; "myiasis intestinalis" for 
those in the alimentary canal; and "myiasis narium" for larvae in the 
nose. The presence of larva? in the nose is rather accidental in this 
country and usually due to the "screw-worm." In tropical countries this 
type of myiasis is quite common. 

The larvae of the ox-warble or bot-fly (Hypoderma lineata Villers) 
sometimes occur in man. There are various cases recorded, mostly of 
children, where, in the winter time, a larva is observed under the skin, 
usually in the neck or shoulders, and upon removal proves to be the 
larva of the heel fly in the second stage. Bot infestation is sometimes 
called "creeping worms," and many cases have been recorded by army 
surgeons on the Mexican border. These cases are probably contracted 
by men sleeping in stable yards. 

Descriptions of larvae or maggots 2 

All the larvae mentioned here are broadest near the tip or tail of the 
body, and taper forward to the head. 

2 In the following discussion the visible body segments are numbered from head 
to anus irrespective of their scientific nomenclature. — W. D. Pierce. 



142 SANITARY ENTOMOLOGY 

The larva is divided into fourteen parts, of which eleven are distinct, 
called segments, and the first segment is the head. The head appears to 
be bilobed, or divided into two parts when viewed from above, and each 
lobe bears a minute cylindrical tubercle or papilla (fig. 13). Below is 
the mouth opening; at one side and above it is the pair of mandibles or 
great hooks (fig. 13). The second segment or prothorax bears on each 
side, in the full grown larvae, a short fan-shaped process called the an- 
terior spiracle. The eleventh body segment which might be taken for the 
last is often a fusion of the seventh to tenth abdominal segments. The 
eighth abdominal segment can always be identified by the stigmal plates 

Stigma f fic/cl (containing posterior sh'gmaf p/ates) 




tfooks 



\ Anal tu here k. Ventral fusiform area. Latera/ fusiform area. 

§s Anterior so/rac/e. 



•B 



Fig. 13. — Characters of a muscid fly larva. (Greene.) Segment 1 is the head; 2-4 
are thoracic segments; 5-11 are abdominal. Segment 11 really contains the seventh 
to tenth abdominal segments, the spiracles being on the eighth, the anus in the tenth. 

or lobes. The ninth and tenth are usually small and ventral and enclose 
the anus. For further details see fig. 13. 

Table to Separate the Larvae {Maggots) 

I. Spiny larvae. 

1. A larva with the body flattened; down the middle of the back are 
two rows of spines or processes, there are also two rows along 
the under side and a single row of spines along each side. These 
spines or processes are pointed and covered with many bristles. 
There are also two stigmal plates on top of the last segment. 
(Figs. 14-16.) Fannia canicularis. 

2. The larvae of Fannia scalaris are similar (figs. 17-19), but the 
processes have fewer side branches. 

II. Smooth larvae. 

A. With one great mouth-hook ; slits in stigmal plate windi/ng. 

1. Body broadly rounded at rear end, without spines. Stigmal plate 
with three winding slits (figs. 20 to 22). Musca domestica. 



COMMON FLIES AND HOW TO TELL THEM APART 143 

2. Body same as above species, stigmal plate with three S-shaped 
slits (figs. 23, 24). Stomoxys calcitrans. 

B. Two great mouth-hooks ; slits in stigmal plate not xvinding. 

1. Body slightly rounded at rear end, faintly spined and with three 
short, pointed slits in stigmal plate (figs. 25, 26). 

Muscina stabulans. 




Fig. 14. — Larva of the little house fly, Fannia canicularis. Greatly enlarged. (Howard 
and Pierce, drawing by Bradford.) 




Fig. 15. — Dorsal view of eighth abdominal 
segment of the larva of Fannia canic- 
ularis. Very highly magnified. (Draw- 
ing by Bradford.) 



Fig. 16. — Ventral view of terminal seg- 
ments of Fannia canicularis ; the ninth 
and tenth segments are comprised in 
the small zone around the anus. Very 
highly magnified. (Drawing by Brad- 
ford.) 



Stigmal plates wide apart, each with three straight slits nearly 
transverse to the body and a distinct button (figs. 27, 28). 

Calliphora erythrocephala. Calliphora vomit oria. 
Stigmal plates about half their diameter apart, each with three 
straight slits directed somewhat downward (fig. 31). 

Lucilia sericata. 
Stigmal plates less than their own diameter apart, each with 
three straight slits pointed downward; no button (figs. 29, 3j0). 

Chryso my a ma cell a via . 



144 SANITARY ENTOMOLOGY 

5. Stigmal plates at bottom of a deep pit ; each plate has three 
slits pointing downward, plates less than their diameter apart ; no 
button. Sarcophagidae. 



Fcmnia canicwlaris Linnaeus and Fannia scalaris Fabricius 

These larvae are brownish yellow in color. The body is quite flattened, 
narrow and pointed in front. The peculiar spines or projections on the 
body will separate them from the other species. The larva averages 
nearly three-eighths of an inch in length (figs. 14-19). (See Chapter 
VIII.) 




Fig. 17. — Larva of Fannia scalaris, the latrine fly, greatly magnified. 
Pierce, drawing by Bradford.) 



(Howard and 




Fig. 18. — Dorsal view of eighth abdominal 
segment of the Fannia scalaris. Very 
highly magnified. (Drawing by Brad- 
ford.) 



Fig. 19. — Ventral view of terminal seg- 
ments of Fannia scalaris; the ninth 
and tenth segments are comprised in 
the small zone around the anus. Very 
highly magnified. (Drawing by Brad- 
ford.) 



Since the larvae of this genus feed on fruit and vegetables that are 
just beginning to decay, one can readily see that they are often swallowed 
by people. There are many records of the passage of larvae or maggots 
of this genus. At least some species of this genus breed in human feces, 
therefore they may be possible conveyers of disease. 



Musca domestica Linnaeus 

The larva of the house fly is slender and tapering in front and large 
and somewhat rounded behind. From above, the head is divided into two 



COMMON FLIES AND HOW TO TELL THEM APART 145 

parts with a tiny papilla on each side (fig. 20) and there is but one 
great hook. The anterior spiracles (fig. 21) show six or seven lobes; 
on the under side of the sixth and following segments there is a trans- 
verse, swollen area, wider in the middle and somewhat pointed toward 
each end. These areas are provided with minute teeth. The area is 
slightly prominent and shows two approximate processes. The stigmal 
field is barely if at all concave and not outlined by tubercles ; the posterior 
spiracles (fig. 22) are prominent, less than their own diameter apart 
and each with three winding slits and a button at the base. In some 
cases two of the winding slits are apparently connected. The second- 
stage larvae has two straight slits in each stigmal plate, while in the first 
larval stage there are two smaller slits on a tubercle each side of the 






Fig. 20 (left). — Larva of Musca dom-estica; dorsal view of head and porthorax. (Greene.) 

Fig. 21 (center). — Larva of Musca domestica; lateral view of terminal segments. 
(Greene.) The spiracles are located on the eighth abdominal segment. The ninth 
and tenth segments are ventral and not very distinct, enclosing the anus. 

Fig. 22 (right). — Larva of Musca domestica; enlarged sketch of right stigmal plate. 
These plates are less than their breadth apart. (Greene.) 



middle and in this stage there are no anterior spiracles. (See Chapter 
VIII.) 

The larva of the house fly is rarely swallowed, but there are records 
to that effect. It sometimes breeds in decaying fruits and vegetables. 
The principal breeding place is in horse manure. It also breeds in human 
excrement and because of this habit it is very dangerous to human 
beings. 

Stomoxys calcitrans Linnaeus 

The larva of this species is very similar to that of the house fly, with 
a single great hook; the anterior spiracles have five lobes (fig. 23); the 
sixth and following segments have each an area on the under side pro- 
vided with tubercles ; this area is wider in the middle ; anal area has two 
submedian tubercles and three each side of these; above them is a row 



146 SANITARY ENTOMOLOGY 

of minute granules, ending each side in a larger granulate tubercle ; there 
are no tubercles outlining the stigmal field; the stigmal plates are sub- 
triangular, about one and one-half times their diameter apart, black, 
and each with three pale areas containing an S-shaped slit (fig. 24). 
These slits are never near each other like in the house fly, and there is no 
apparent button. 

This larva commonly breeds in manure of various kinds, but also in 




Fig. 23. — Larva of Stomoxys calcitrans: enlarged sketch of thoracic spiracles. (Greene.) 

decaying matter, and is not often passed by people, but there is one 
record. Horse manure, cow manure, and warm, decaying vegetation, like 
old straw and grass heaps, are common breeding places. 




Fig. 24. — Larva of Stomoxys calcitrans: enlarged sketch of right stigmal plate. These 
plates are one and one-half times their breadth apart. (Greene.) 



Muscina stabulans Fallen 

Head of larva (fig. 25) divided into two parts from above, no dis- 
tinct papilla; two great hooks close together; anterior spiracles with 
about six lobes (fig. 25b). The surface of the segments is mostly smooth. 
Beginning with the fifth segment, on the under side, there is a basal, 
transverse, swollen area, furnished on the crest with rows of teeth; each 
of these areas is divided on the median line. On the next to the last 
segment there is a similar area at the tip, but not divided. The seg- 
ments below also show a transverse line before the middle. The last 
segment has the anal basal area with spines, but not very prominent, 
and bears a median and three lateral tubercles with spines. The tubercles 



COMMON FLIES AND HOW TO TELL THEM APART 147 

are nearly in a transverse row. The rounded tip of the body (fig. 25c) 
shows, across the middle, faint traces of four low cones. The stigmal 
plates (fig. 26) are scarcely elevated, black, less than their own diameter 
apart, and each with three very short slits pointing towards those of the 
opposite plate. 

This larva is common in decaying vegetable matter; and has been 
reared from rotten apples, pears, squash, mushrooms and dead insect 



> a 




Fig. 25. — Larva of Muscina stabulans: a, Side view of head and prothorax; b, an- 
terior or thoracic spiracles; c, side view of terminal segments of abdomen. 
(Greene.) 

larvae. In one case a considerable number were passed by a child suf- 
fering with summer complaint. Laboulbene records larvae of this species 
vomited by a person suffering from bronchitis. 




Fig. 26. — Larva of Muscina stabulans: enlarged sketch of right stigmal plate. These 
plates are less than their breadth apart. (Greene.) 

Calliphora erythrocephala Meigen 

The head of this larva is distinctly divided into two parts from above 
(fig. 27, side view of head) ; each part or lobe has a tiny papilla. There 
are two well separated mouth hooks. The anterior spiracles have from 
nine to twelve lobes. Beginning with the third, each segment shows an 
apical swollen ring or girdle, whose surface is scabrous (roughened like 
a file) ; these rings are broader below than above, and are here notched 
on the posterior middle. Each ventral segment, beginning with the fifth, 
is divided by a transverse groove near the middle. The anal area shows 
a smooth median process, divided in the middle, and at each outer corner 
is a cone. The stigmal field is rather concave, the upper lip with three 
small tubercles on each side, the lower lip with two larger tubercles on 
each side, and a median pair smaller and lower down. The stigmal 
plates are about once and a fourth their diameter apart, each with three 



148 SANITARY ENTOMOLOGY 

simple straight slits directed slightly downward but mostly toward those 
of the opposite plate; the button is distinct (fig. 28). 

The blow-fly deposits eggs on dead animals, and also on fresh and 
cooked meats. As such are often accessible to them in pantries, it is 
readily seen that many larvae are swallowed by people each year; there 
are, however, comparatively few records published, probably because the 
polluted food causes no trouble. 

Calliphora vomitoria Linnaeus 

This larva appears to be identical with that of Calliphora erythroceph- 
ala. There seem to be no visible characters to separate it from this 
latter species (figs. 27 and 28). The habits are about the same. 




Fig. 27. — Larva of Calliphora erythrocephala: side view of head and prothorax. 
(Greene.) 

Lucilia sericata Meigen 

Body rather stout, not slender in front. The head is distinctly 
divided into two parts or lobes, with distinct papilla(figs. 31a, b). The 

^^ 

Fig. 28. — Larva of Calliphora erythrocephala: enlarged sketch of left stigmal plate. 
These plates are one and one-quarter times their breadth apart. (Greene.) 

two great mouth hooks are well separated. The anterior spiracles are 
provided with about eight lobes. The surface of the body is mostly 
smooth; the sides of segments 3, 4 and 5 are bilobed; beginning with 
segment 6 there is a basal ring girdle, roughened. These girdles on seg- 
ments 6 to 9 are widened on the middle of the under side of the larva; 
the sides are also swollen, but not plainly bilobed, except those near 
the tip. The under sides of the segments are transversely divided by a 
line or furrow in the middle. The last segment is short, the stigmal 
field occupying most of the tip. The stigmal field has a slightly de- 
pressed, upper lip with three sharp tubercles on each side, the interme- 
diate one hardly smaller than the others ; and a lower lip with two large, 



COMMON FLIES AND HOW TO TELL THEM APART 149 

sharp tubercles on each side, and a median pair more remote from the 
margin (fig. 31c). The anal area is rather sunken with a small rounded 
tubercle at each outer corner. The stigmal plates are about one-half 
their diameter apart, each with three straight slits, directed somewhat 
towards each other, but also downward. 




a. (r. C. 

Fig. 31. — Larva of Lwcilia sericata: a, dorsal view of head and prothorax; b, lateral view 
of head and thorax; c, lateral view of last abdominal segments. (Greene.) 

This larva is mentioned on account of the adult which is very likely 
to be met with. This larva is mostly injurious to sheep. Meinert has 
reared another Lucilia (L. nobilis Meigen, of Europe) from larvae taken 
from the ears of a sailor. 




Fig. 29. — Larva of Chrysomya macellaria: enlarged sketch of side of head and pro- 
thorax. (Greene.) 

Chrysomya macellaria Fabricius 

The head from above is distinctly bilobed (fig. 29). There are two 
distinct hooks. The anterior spiracles are very short, and contain only 




Fig. 30. — Larva of Chrysomya macellaria: enlarged SKetch of left stigmal plate. These 
plates are less than their breadth apart. (Greene.) 



7 lobes (fig. 29). The posterior upper part of segment 1 is swollen and 
with many spines (fig. 29). Each of the following segments (except 2) 
has a basal, swollen ring, armed with teeth pointing backward, the teeth 
of the front rows are always larger. Beginning with segment 6 the under 



150 



SANITARY ENTOMOLOGY 



part of each ring is much broadened and divided transversely by a narrow 
smooth space. On segments 5 to 10 there is on each side behind a fusi- 
form swollen area pressing against the swollen ring of the next segment ; 
this area also has spines. The tip of the body shows on the dorsal part 
a great cavity, in the bottom of which are the stigmal plates, each with 
three straight slits, those of one sub-parallel to those of the other ; 
there is no button (fig. 30). Behind this cavity is a high, transverse, 
spiny crest ; and the ventral part of the tip shows an area covered with 
spines bearing two rather widely separated, prominent, smooth tubercles. 
The upper edge of the tip shows four small conical tubercles. 













si 


* 


*^N Be, ^H 


\;.. :.v;;. : : ; :;;-;:-/-4 ? 3:« : ;a'S>' 




■ " " '- .^4 


J- 




/' I 


: \ 














s 






k 


% 40 




'' US 

■ 










. .: 


BHR^v^H 




> 




BB»*-^_^j|h[ 


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,^yHp* . 





Plate IV. — Screw worm injury to a yearling calf. (Bishopp.) 

The larva of this insect is called the "screw-worm," and occurs in 
sores and wounds of domestic animals and also in man. There are 
various records of its presence in the ears and nose, or nasal cavities, 
of people ; in swellings near the nose ; in a boil under the arm ; under the 
skin of a child ; and in the navel of a child. It is hardly a possible 
factor in intestinal myiasis of man, and most of such recorded cases 
probably belonged to some species of Sarcophaga whose larvae are very 
similar in appearance to those of the screw-worm. 



Sarcophagidae 

The Sarcophagidae have two great hooks, and the posterior stigmal 
plates have three slits as in Calliphora erythrocephala and Lucilia seri- 



COMMON FLIES AND HOW TO TELL THEM APART 151 

cata. However, these slits are not directed toward those of the opposite 
plate but are sub-parallel to them. The stigmal field is strongly depressed 
to form a deep pit, and the stigmal plates are at the bottom of this pit. 
The segments of the body bear complete rings of spinose areas, and often 
supplementary pads on the sides. 

Sarcophaga larvae prefer animal matter, breeding extensively in car- 
casses. They have been found in cheese, oleomargarine, pickled herring, 
dead insects, and human feces. A species was also reared from decaying 
vegetables. 

BIBLIOGRAPHY 

Banks, N., 1912. — The Structure of Certain Dipterous Larvae with Par- 
ticular Reference to those in Human Foods. U. S. Dept. Agr., Bur. 

Ent., Tech. Bull. 22. 
Hewitt, C. G., 1910. — The Structure, Development and Bionomics of the 

House Fly, Masca domestica Linn. 
Howard, L. O., 1910. — A Contribution to the Study of the Insect Fauna 

of Human Excrement. Proc. Wash. Acad. Sci., vol. 2, pp. 541- 

604. 
Howard, L. O., and Hutchison, R. H., 1915. — House Flies. U. S. Dept. 

Agr., Farmers' Bull. 679. 
Howard, L. O., and Hutchison, R. H., 1917.— The House Fly. U. S. 

Dept. Agr., Farmers' Bull. 851. 
Lallier, P., 1897. — Etude sur la Myase du Tube Digestif chez l'Homme. 

These Faculte de Medecine de Paris, pp. 120, 1 pi. 
Lintner, J. A., 1882. — Injurious Dipterous Insects. 1st Rept. Inj. 

Ins., New York, pp. 168-227, figs. 45-67. (Anthomyiida?.) 
Lowne, B. T., 1892, 1895. — The Anatomy, Physiology, Morphology, 

and Development of the Blow-fly (Calliphora erythrocephala). 2 

vols., London, 778 pp. 52 pis., 108 figs. 
Newstead, R., 1907. — Preliminary Report on the Habits, Life-cycle, and 

Breeding Places of the Common House Fly (Musca domestica), as 

Observed in the City of Liverpool, with Suggestions as to the Best 

Means of Checking Its Increase. Liverpool, 23 pp., 14 figs. 
Packard, A. S., 1874. — On the Transformation of the Common House 

Fly, with Notes on Allied Forms. Proc. Bost. Soc. Nat. Hist., vol. 16, 

pp. 136-150, 1 pi. 
Patton, W. S., and Cragg, F. W., 1913.— A Textbook of Medical 

Entomology. 
Perez, C, 1910. — Recherches Histologiques sur la Metamorphose des 

Muscides (Calliphora erythrocephala). Arch. Zool. Exp., 274 pp., 

16 pis. 



152 SANITARY ENTOMOLOGY 

Riley, W. A., and Johannsen, O. A., 1915. — Handbook of Medical 

Entomology. 
Walsh, B. D., 1870. — Larvae in Human Bowels. Amer. Ent., vol. 2, pp. 

137-139. (Homalomyia.) 



CHAPTER X 

The Control of the House Fly and Related Flies 1 
W. Dwight Pierce 

We have now come to one of the greatest problems in Sanitary 
Entomology ; the control of the treacherous flies that visit our homes but 
to bring sickness and death. The anti-fly measures may be classed as 
repressive and palliative, and of course the first are the most impor- 
tant. 

THE FLY MUST BE FOUGHT WHILE BREEDING AND BE- 
FORE IT HAS A CHANCE TO SPREAD DISEASE. Many persons 
object to the anti-fly-breeding measures because of cost, but no cost is too 
great if thereby we prevent epidemics and the loss of thousands of 
lives. 

Inasmuch as we are dealing with the fly as a municipal, industrial, 
rural, home, and army problem, the subject will have to be handled 
topically. 

REPRESSIVE MEASURES 

Striking the Source 
Manure 

The house fly normally breeds in horse manure, but may also breed 
in the manure of other domestic animals. It is apparent that this then 
is the first and most difficult point to strike. 

The disposal of manure is a matter which must be controlled in all 
municipalities and wherever there are large congregations of people. 
For this reason it is an acute problem of army camps and cantonments. 
In cities it is most acute in stockyards, sales stables, livery stables, and 
contractor camps. It is a problem on every farm and with every 
individual who owns a horse, or hog. 

Chemical Treatment. — Manure is a valuable product and every effort 
should be made to conserve and utilize it, first rendering it unfit for 
flies. Realizing this, the United States Department of Agriculture had 

1 This lecture was read August 5, 1918, and has been more or less modified to its 
present form. 

153 



154 SANITARY ENTOMOLOGY 

a long series of careful studies made of many chemicals which might be 
applied to manure, in order to determine the effects upon the fly larvae, 
the bacterial activity of the manure, and the fertilizer value of the manure. 
The results have been published in various bulletins hj Hutchison, Cook, 
and Scales with the principal recommendation in favor of the daily treat- 
ment of fresh manure with powdered borax at the rate of 1 pound to 16 
cubic feet, or 0.62 pound per 8 bushel of manure. This will kill about 
90 per cent of the larvae, and is harmless to the manure. Larger amounts, 
however, may have a deleterious effect. 

They also found that a water extract of hellebore, prepared by adding 
1/2 pound of powder of hellebore to 10 gallons of water, which after 
stirring is left for 24 hours, is effective at the rate of 10 gallons to every 
8 bushels (10 cubic feet). Likewise a mixture of % pound of calcium 
cyanamid and % pound of acid phosphate to each bushel of manure 
gives a larvicidal action of 98 per cent. Unfortunately these last two 
remedies are not available at the present writing. 

Creosote has been recommended by British authorities, but the investi- 
gators mentioned above have found a deleterious effect upon the manure. 
If the primary essential is destruction of fly breeding, and the other 
chemicals are not available for treatment, creosote treatment is effective, 
and there will still unquestionably be fertilizing value to the manure. 
Army sanitarians, especially, can not always use the most approved 
methods, but must rather obtain immediate results with materials and 
means at hand. 

Maggot Traps. — Hutchison discovered an application of the habit 
of the fly maggots of migrating from the manure piles before pupation, 
when he developed the maggot trap which consists of a slatted platform 
over a cement or metal water-filled basin (fig. 32). Such platforms can 
be built of sufficient size and number to hold the accumulations of 
manure for a period of about two weeks, after which time it is unfavorable 
for house fly development. The larvae migrate from the pile and fall 
into the water and drown (plate VIII). 

Storage in Bins. — The house fly is averse to darkness and various 
contrivances have been devised for the dark storage of manure, in pits, 
tightly closed boxes, windowless rooms, etc. (see plate V). For small 
stable accumulations, especially in cities, perhaps this furnishes one of 
the best means of temporary storage. It is a good plan to use fly traps 
in connection with manure bins (see fig. 33). 

Stacking. — Manure may be stacked in such a way as to greatly mini- 
mize, if not entirely prevent fly breeding. A stack built up by the driving 
of the wagons over the pile and dumping thereon becomes very compact 
and the internal heating is quite destructive to the fly larvae. The sides 
of such a pile should be compacted and the loose materials on the ground 



CONTROL OF THE HOUSE FLY AND RELATED FLIES 155 




Fig. 32. — A maggot trap for house-fly control. View of the maggot trap, showing the 
concrete basin containing water in which larvae are drowned, and the wooden 
platform on which manure is heaped. (Hutchison.) From U. S. Dept. Agr. Bull. 
200, plate 1 (larger), or farmer's bull. 851, fig. 14 (as above). 




Plate V. — Manure box with fly trap attached. (Bishopp.) 



156 SANITARY ENTOMOLOGY 

thrown onto the pile or raked up and burned. The edges of the pile and 
the ground around it may be treated with borax or oiled with creosote 
or crude oil. 

In Panama it is a custom to set fire to the manure pile and burn it 
down about a foot, thus covering the entire pile with ash. 

Broadcasting. — Often on farms it is practicable to take the daily 
accumulation of manure and spread it over the fields. When the weather 
is dry, or very hot, or too cold for fly breeding, this method is a very 
desirable means of handling the manure problem, but the broadcasting 
of fresh manure on moist ground in cloudy or moist weather may give rise 
to great quantities of flies unless it is spread very thinly and the larvae 
are not well matured when the manure is scattered. An illustration of a 
manure spreader is given in plate VI, An undesirable method of spread- 
ing manure is shown in plate VIII. 

Collection of Manure. — It is important that manure be collected and 
removed from the vicinity of habitations at regular periods, sufficiently 
frequent to remove the possibility of its becoming a source of fly breeding. 
In army camps it is imperative that manure be daily removed from all 
stables, picket lines and stable yards. In cities the ordinary accumula- 
tions of private stables should be required to be removed once each week, 
but in the meanwhile it must be either stored in bins or on maggot traps, 
or daily treated with borax. The accumulations of large stables, livery 
and feed stables, stockyards, etc., should be required to be removed daily. 

We may obtain some of our best illustrations of the proper handling 
of manure from army practices followed during the Great War. Army 
discipline makes it possible, when the command is properly educated to 
the importance of it, to control the manure problem more effectively 
than under any other condition on a large scale. Tremendous quantities 
of manure were produced in cantonments and shipped in car or train 
loads daily. Most of the larger cantonments that were located in pro- 
gressive rural sections were able to farm out the manure to individual 
farmers or to sell to contractors who shipped it by the carload daily 
and distributed it to the rural population. When unable to do this the 
army officials were compelled to resort to storage or destruction of the 
manure as discussed in other paragraphs. 

Loading platforms for shipment of manure need to be carefully 
watched and kept under strict supervision. If these platforms are loosely 
built of framework elevated above the cars, much of the manure falls 
through the cracks and over the edges, and great accumulations arise at 
the sides of the tracks and between the tracks. A properly constructed 
loading platform should have a cement base with the tracks imbedded in 
the cement and should be daily flooded, the washings being swept into 
piles and oiled, and burned when dry enough. The writer has found the 



CONTROL OF THE HOUSE FLY AXD RELATED FLIES 157 




Fig. 33. — Use of flytrap in connection with manure bin. A. Block of wood set in 
ground to which lever raising door is hinged. (Bishopp.) From Fanner's Bull., 
U. S. Dept. Agr., No. 734, fig. 6. 




-4* 



Plate VI. — Manure spreader (Bishopp.) 



158 SANITARY ENTOMOLOGY 

accumulations under loosely built platforms to be a fertile fly breeding 
condition. 

Shipment of Manure. — When manure is shipped by car, the railroads 
should be required to remove it promptly and the contractors should be 
required to unload promptly and distribute it in such a manner that it 
will not be a source of flies to the community where it is unloaded. If 
unavoidable delays do not permit prompt handling of this manure, it 
should be treated with borax water. 

Cleaning Up. — Well drained cement floors in stables are by all means 
the most sanitary and lend themselves best to cleanliness. If it is 
impracticable to have cement floors, the dirt floors should be sloped to 
drain well and should be made hard by saturation with oil or mixing 
with other soils which pack better, as certain types of clay. The floors 
should be swept daily after removal of the manure, and sprinkled with 
borax water, or limed. Frequent treatment with a creosote compound 
is of value. The ground around hitching posts and picket lines becomes 
soggy with urine and manure, unless treated by digging up the soil for 
several inches and saturating it with oil, and then tamping it hard. 
Stable yards should not be allowed to become filled with manure. They 
should be swept, or raked or scraped up daily and the manure removed 
(see plate VII). A filthy stable yard may be the source of scourges of 
flies. 

Incineration. — When manure cannot be sold, chemically treated, 
farmed out, or stacked to prevent fly breeding, it must be burned. This 
is often a necessity in army encampments. In dry sections the windrow 
incineration may be practiced. The teams drop their loads in great, 
long windrows, the horses straddling the rows. These are spotted with 
oil and set afire. The wooden chimney windrow which was practiced at 
Edgewood Arsenal consists of a windrow of logs piled to form a horizontal 
chimney over which the manure is piled and then fire is set to the wood. 
The hillside incinerator devised by Dr. Mann at Quantico, Virginia, 
consisting principally of iron rails and chicken wire screen or gratings 
under which a fire is burning, is practical for small camps. The hammock 
incinerator, a woven wire hammock or two suspended over a fire, will 
do as a temporary expedient for a small detachment on temporary duty, 
or for field parties of hunters or investigators. Furnace incinerators can 
reduce the manure to an ash and save whatever is of value in the ash. 

Need of Rigid Inspection. — It is not only army camps that need 
to have a rigid inspection system as regards manure disposal. Every city 
which has any regard for the public health should insist on proper 
inspection and regulation of stables and places where manure accumulates. 
It is not uncommon in many cities to see boxes of manure in alleys swarm- 



CONTROL OF THE HOUSE FLY AND RELATED FLIES 159 




Plate VII. — Road drag in use scraping manure in a cow lot on a Tennessee farm. 
(Bishopp.) 




Plate VIII. — Undesirable conditions which are overcome by use of the maggot trap. 
A manure pile covering a large area and having little depth. Illustrating the 
conditions which favor the greatest loss of nitrogen, and at the same time offer 
the best breeding ground for flies. (Hutchison.) From U. S. Dept. Agr. Bull. 
200. Plate III. 



160 SANITARY ENTOMOLOGY 

ing with fly larvae, or to find piles of manure standing for weeks in front 
of livery stables, even on the sidewalks. 

In one small city, the writer, in passing by a side track where certain 
grain companies unloaded straw and feed, using horse drawn wagons, 
noticed that the ground along these tracks was a thick mixture of 
rotting straw, grain, and horse droppings. This was across the street 
from the city market where flies were swarming in the fish stalls especially. 
Only a personal tour of inspection by a trained observer would turn 
up many of the most important sources of fly breeding. 

Garbage 

Needless to say it is necessary that garbage be kept in fly-tight cans 
and that it be removed daily, or every third day when the amount is 
small. The army method of building a screened box for holding the 




Fig. 34. — Top of garbage can with small balloon fly-trap attached. (Bishopp.) 

garbage cans is very good, and would be an excellent plan for hotels and 
restaurants especially. A fly trap on a garbage can will catch many 
flies (fig. 34). Empty garbage cans are very attractive to flies. The 
writer has seen many wagons full of empty cans which had been washed 
in lye water, swarming with flies, returning to camp. It is necessary to 
wash the cans in a creosote compound. Householders are very careless 
of the cleanliness of their garbage cans. If they can not wash them they 
can rinse them with a hose and treat with a creosote compound or lye 
water. When garbage is farmed out for feeding to pigs the farmers 
should be bound by contract not to take more than their pigs can consume 
in a day. The feeding pen should have a cement foundation so that it 
can easily be cleaned. The remains of the day's feeding should be burned. 
Many municipalities, as well as army camps, dispose of the garbage by 
incineration. Others sell to contractors for reclamation. Some parts of 
the garbage are not of value for feeding or reclamation and the writer 
has seen instances where such material was thrown on dumps with tin 
cans and trash and not burned. Great vigilance is necessary at all waste 



CONTROL OF THE HOUSE FLY AND RELATED FLIES 161 

dumps to see that no fly-breeding material is dumped anywhere except on 
incinerators. 

Grease traps at kitchens of mess halls, and at garbage can washing- 
platforms are attractive places for fly breeding and should be kept clean 
and treated with creosote compounds. 

Excreta 

The disposal of human excreta is a great problem in all communities, 
but becomes acute in army and construction camps and at camping 
resorts. In temporary army camps where latrines are necessary, the 
excreta must be disposed of daily. The excreta may be saturated with 
oil, covered with straw and burned daily. They may be treated with 
lime or borax or creosote, and buried, gradually filling the latrine. They 
may be removed daily, hauled to an incinerator and burned. Private and 
public camping grounds should be as carefully protected in this manner 
as an army encampment. Probably much education is necessary to 
accomplish this practice. When a sewage system is available, the diffi- 
culties are less, but care must be exercised to maintain the sewers in good 
repair. If a manhole does not operate properly and sewage accumulates 
on the walls, flies will breed there. If the main leaks and washes away 
the covering soil, flies will breed in the seepage. The writer has personal 
knowledge of just such insanitary conditions. At some point in the 
system, unless septic tanks are installed, the sewage will empty into a 
stream. The stream bed must be kept free of obstructions, with straight 
banks. No trees, shrubs, grass or other obstacles must interfere with 
the steady flow of the sewage, for behind every branch, or root, or weed 
solid excreta will accumulate and flies will breed. In case excrement 
accumulates in spite of all vigilance, it should be oiled, burned off and 
moved on with all expedition, immediately upon discovery. The most 
revolting sight the writer has ever experienced was caused by the damming 
up of a sewage-carrying stream, causing a tremendous accumulation of 
solid excreta which was fairly alive with wriggling maggots and black 
with swarms of flies, and this was but a scant quarter mile from a 
a great army camp, and typhoid fever was present. Only quick meas- 
ures averted an epidemic. 

Carcasses 

Bodies of animals offer great opportunities for the breeding of many 
species of flies and especially for the spread of disease. Carcasses should 
be removed as soon as possible after discovery. The best way to dispose 
of them is to burn them. If they cannot be burned they should be treated 
with quicklime and buried. On the battlefield it is often impossible to 



162 SANITARY ENTOMOLOGY 

burn or bury. Foreman and Graham-Smith have ably shown the value 
of coal tar creosote oil as a deodorizer, preventive of decomposition, and 
fly destroyer in carcasses. This subject is fully treated by Mr. Bishopp 
in the chapter on myiasis (Chapter XIII). 

Miscellaneous breeding places 

Factory waste, rotting vegetable matter, the accumulation of debris 
along shore lines, chicken yards, pig pens, alleys, streets which are not 
swept, gutters, etc., furnish fly-breeding places (see Chapter XI). Mr. 
Laake's able presentation of packing-house problems in another lecture 
covers that subject sufficiently (see Chapter XXXIII). 

PALLIATIVE MEASURES 

In view of the fact that flies can come great distances, possibly even 
over 50 miles as indicated by Ball at Rebecca Shoal, the sanitarian is not 
always responsible for all the flies that visit the locality under his juris- 
diction. There is therefore always the necessity of taking measures 
against the flies themselves, although this is entirely secondary to the 
prevention of breeding. 

Screening. — All foods must be protected from flies because many of 
the flies which visit foods lay eggs therein. This is especially true of 
meats which are attacked by blow flies, and cheeses which are attacked 
by skippers. City markets should not expose meats for sale uncovered, as 
the attraction to flies is too great. A well-screened house will have the 
least trouble from flies. In army camps anywhere in the United States 
all sleeping quarters, kitchens, and mess halls should be well screened 
against flies. All hotels throughout the country, especially in rural com- 
munities, should be required to screen all windows and doors. 

The fly situation around small country hotels is by far the most 
repulsive that can ordinarily be found in any community. Very little, 
if any, care is taken of the privies and the flies come directly from there 
to the kitchen and dining rooms. 

Screening of garbage cans has been mentioned and is an admirable 
procedure. A screened enclosure around privies and latrines would assist 
in keeping flies away. 

Fly Traps. — Fly traps of many different designs have been devised. 
The most efficient is the cone and cylinder type devised by Bishopp (fig. 
35). The Hodge window trap is good. A small cone and cylinder trap 
may be inserted in the lid of garbage cans (fig. 34). The principle of all 
different traps is the attraction of the flies by a good bait, and the 
arrangement of the trap so that once there the fly can not get away. At 



CONTROL OF THE HOUSE FLY AND RELATED FLIES 163 

all places where flies congregate, as markets, eating places, packing 
houses, etc., the liberal use of good fly traps is a very good measure. As 
baits for such traps the following suggestions have been made. 

1. Milk. 

2. Overripe or fermenting bananas, crushed and placed in the bait 

pan. 

3. Bananas and milk are better than either separately. 

4. A mixture of 3 parts water, 1 part molasses, is good after it has 

fermented for a day or two. 



D ^-^ 



I-** 




Fig. 35. — Conical hoop fly trap; side view. A, Hoops forming frame at bottom. B, 
Hoops forming frame at top. C, Top of trap made of barrel head. D, Strips 
around door. E, Door frame. F, Screen on door. G, Buttons holding door. H, 
Screen on outside of trap. /, Strips on side of trap between hoops. J , Tips of 
these strips projecting to form legs. K, .Cone. L, United edges of screen form- 
ing cone. M, Aperture at apex of cone. (Bishopp.) From Farmer's Bull, U. S. 
Dept. Agr., No. 734, figs. 5, 1. 



5. A mixture of equal parts brown sugar and cheese or curd of sour 

milk, thoroughly moistened, is good after it has been allowed 
to stand three or four days. 

6. Mucous membrane from the lining of hogs' intestines is attractive 

to blow-flies and other meat-infesting flies, as well as the house 
fly. This is available for fly traps at packing houses. 

7. Ordinary fish and meat scraps. 

8. Moistened garbage. 

These baits are of little value if allowed to dry out. It is not uncom- 
mon to see fly traps standing out in the sun near garbage cans, witli no 
flies within but plenty of flies around, and the bait dried out by the 
sun. The fly trap must be more attractive than its surroundings. When 
baits are used which will permit of the development of maggots in them, 



164 SANITARY ENTOMOLOGY 

the pans should be scalded and then emptied, and rebaited, every three 
days. 

Fly Paper. — Sticky fly paper has distinct merits and in the presence 
of abundance of flies should be used. The hanging pyramid strips are 
considered better by some sanitarians than the flat papers. 

Poisoned Baits. — Many fly poisons are on the market. Any kind of 
poisoned bait is dangerous in the presence of children or ignorant persons 
as there are many recorded fatalities to children from drinking fly liquids 
or licking poisoned papers. 

Phelps and Stevenson, 1917, 2 have given a very thorough presentation 
of the question of fly poisons. Their bulletin should be consulted by any 
one desiring to go very far into this phase of the subject. 

The most efficient strength of formaldehyde is 0.5 to 1 per cent, which 
is equivalent to 1.25 to 2.5 per cent of the 40 per cent solution sold as 
formalin. 

A muscicide considered by them as even superior Jto formaldehyde in 
many ways is an aqueous solution of 1 per cent sodium salicylate plus 10 
per cent brown sugar. 

They used sodium arsenite as the basis for their experiments. This 
was made up in stock solution as follows: 

Dissolve 4.95 grams pure sublimed arsenious oxide As 2 3 and 20 
grams pure sodium carbonate in about 300 cc. of distilled water by heat- 
ing. When the solution is complete the liquid is cooled to 20° C. 
and the volume made up to 1,000 cc. with distilled water. Ten cc. of the 
stock solution are diluted to 1,000 cc. with distilled water and this is 
called by them the standard arsenite solution, or one-thousandth normal 
solution. 

Sodium fluoride solution, 1 per cent, gave a mortality equal to that 
of the standard arsenite solution. 

An interesting feature of their investigation was the reduced effective- 
ness of these poisons with lowered temperatures. 

Fly Sprays. — In the armies flies often congregate in tremendous 
numbers and some kind of spray is necessary to kill them. Maxwell- 
Lef roy handed me the following formula : 

1 tablespoon formaldehyde. 

% pint lime water. 

14 pint water. 

Kirk recommends as a spray in latrines and tents a light oil mixed 
with three or four parts of water well shaken. Rubber tubing should 
not be used in the spray. A coarse atomizer such as is used in green- 
houses is serviceable. 

2 Experimental Studies with Muscicides and Other Fly Destroying Agencies, Hy- 
gienic Lab,, Bull. 108. 



CONTROL OF THE HOUSE FLY AND RELATED FLIES 165 

Bacot recommends a kerosene emulsion of S parts soft soap com- 
pletely melted by heat in 15 parts of water and the addition up to 100 
parts of kerosene or other light burning oil, and churning up to an 
emulsion. This may be kept indefinitely and diluted with water to about 
1 part emulsion to 10 parts water content. 

Protection of Animals. — Animals are seriously bothered by the pester- 
ing of flies. Any kind of netting that the animal can shake to disturb the 
flies is of some value. The question of repellents is one upon which many 
investigators have labored. Graybill, 1914, 3 summarizes the results of 
these investigations. Those formulae most in use all contain crude 
petroleum oil and usually soap. 

A good stock emulsion recommended by Graybill is made of: 
Hard soap, 1 pound, 
Soft water, 1 gallon, 
Beaumont crude petroleum, 4 gallons, 
Dilute to 1 part emulsion to 3 parts water. 
Bishopp's fly repellent consists of: 
Fish oil, 1 gallon, 
Oil of tar, % ounces, 
Oil of pennyroyal, 2 ounces, 
Kerosene, % pint. 
For dairy cattle, Jensen makes a stock solution of crude petroleum 
with the addition of 4< ounces powdered napthalin, and applies with a 
brush once or twice a week. 

Jensen has also given three formulae of repellents for protecting 
wounds from flies. 
Formula No. 1 : 

Oil of tar, 8 ounces, 
Cotton seed oil to make 3£ ounces. 
Formula No. 2: 

Powdered napthalin, 2 ounces, 
Hydrous wool fat, 14 ounces, 
Mix, into an ointment. 
Formula No. 3: 

Coal tar, 12 ounces, 
Carbon disulphid, 4 ounces, 

Mix ; keep in a well stoppered bottle and apply with a brush. 

It is of the utmost importance that flies be kept at a minimum in army 

camps. We can do no better than cite a few authorities of the various 

armies in support of this. Ainsworth considers the presence of the house 

fly the greatest danger signal to an army in the field. Savas has called 

'Repellents for Protecting Animals from the Attacks of Flies, U. S. Dept. 
Agr. Bui. 131. 



166 SANITARY ENTOMOLOGY 

attention to the connection of flies with the great cholera outbreak in the 
Greek army. At Gallipoli the flies were in amazing numbers, the food was 
black with them as soon as it was set on the table. They filled the tents 
and shelters, settled on the refuse of the camp, and on the unburded dead, 
and by their annoyance multiplied the sufferings of the wounded and 
spoiled the tempers of the hale. The flies have been very bad in France. 
Kirschner states that in the hospitals near the front the enormous number 
of flies presented a serious danger. Maxwell-Lefroy says that in Mesopo- 
tamia the tents and trenches were full of flies. The troops at Salonika 
suffered greatly from diarrhea and dysentery which coincided in appear- 
ance with the abundance of flies. Wenyon and O'Connor found flies in 
Egypt largely responsible for outbreaks of amoebic dysentery among the 
troops. In this connection Dr. Ballou's lecture on flies and lice in Egypt 
(Chapter XXXII) will give an excellent first-hand view of conditions 
in that country* 



CHAPTER XI 

Control of Flies in Barn Yards, Pig Pens and Chicken Yards * 

F. C. Bishop p 

The question of the control of flies in their various breeding media or 
places of breeding can not be well divided in the discussion. Attention 
has been given in a previous lecture (Chapter X) to the general aspects 
of house fly control and the most favorable breeding media and methods 
of handling them have been discussed in a general way. Therefore I shall 
take up the special problems under the three situations listed in the 
title. Adequate care of the manure and other refuse in these situations 
will not only result in the prevention of breeding of house flies in them 
but will also reduce the number of certain other flies which play a part in 
disease dissemination among man and animals, notably the horn fly, stable 
fly, Muscina spp., Fannia spp., certain Sarcophagids and lesser numbers 
of Muscidae known as blow flies, which occasionally breed in hog manure 
and freely in unconsumed animal matter in garbage. 

REPRESSION OF FLIES IN BARN YARD 

The discussion of this problem is bound up closely with that of the 
control of the house fly through the care of horse manure, etc. If 
manure is promptly disposed, of as removed from the barn the yards are 
kept in better condition and the scattered droppings either of horses or 
cattle are less dangerous as regards fly breeding. In drier regions of the 
country these droppings may be practically neglected. Where large 
numbers of horses are kept in sheds or yards, the entire area requires 
treatment. The manure should be scraped up at least as frequently as 
three-day intervals and scattered thinly on fields or composted and 
treated with borax or other larvicides. 

In large stock concentrating points where stockyards and mule sales 
stables are of great extent the problem of disposing of the manure from 
the yards is a difficult one. In the Eastern States it has been the usual 
practice to contract the manure to certain companies or to permit farmers 
and truckers to enter the yards and get manure when they desire it. One 

1 This lecture was read September 9 and distributed September 11, 1918, and is now 
reproduced practically in its original form. 

167 



/ 
168 SANITARY ENTOMOLOGY 

difficulty has been that stock are often kept in a single pen for feeding 
for some time and during this time it has been the rule not to clean up the 
pen. The provision of ample room so that stock may be removed from one 
pen to another to permit cleaning is important. This also applies to 
horse and mule sales stables. The restrictions placed on the horse and 
mule dealers who handle stock for the army have tended to greatly improve 
fly breeding conditions in these stables and yards. I have frequently 
observed these sales stables to be filled with tightly packed manure from 
eighteen inches to three feet deep. In the case of an East St. Louis 
mule sales stable where one company has thirty-five acres under cover, 
the removal of all this manure was an enormous task. Yet it was accom- 
plished so that the company might continue handling stock for govern- 
ment use. The manure was hauled several miles to a fertilizer plant where 
the well decayed part was piled and subsequently dried, ground and sold 
as sheep manure for lawn dressings, while the parts with considerable 
straw were thrown from cars onto rail incinerators and burned, the ash 
being used in fertilizer mixtures. The entire barns and fences were then 
gone over with a sand blast machine which cleaned them of all accumula- 
tion of dust and saliva which had in some cases become quite thick and 
highly glazed. An effort is being made by the authorities in charge to 
have the manure from these stables throughout the country moved at 
weekly intervals. 

The drying of manure and its sale in powdered condition for lawn 
dressings, etc., has attained rather large proportions as a commercial 
enterprise in some of the large cities. This is a satisfactory means of 
disposal of manure and there are good reasons why the practise should 
be extended. 

It appears that where shavings are used for bedding less trouble 
arises from fly breeding than where straw is utilized. This would 
undoubtedly favor reduction in the breeding of Stomoxys also. 

Returning to the question of handling manure in cow lots and small 
barn lots, it is advisable when labor is at hand, especially in dairy yards, 
to pick up the droppings daily or even twice a day. This is greatly 
facilitated by having the yard where cattle congregate in greatest num- 
bers concreted. In large dairy lots it has been found feasible to bring 
the manure together by means of an iron road drag (see plate VII): This 
leaves the manure in windrows so it can be easily shoveled into a wagon. 

For the disposal of manure from dairies and even on the farm no 
method is better than the use of a manure spreader (see plate VI) and 
the scattering of the material thinly on open fields. Of course in cases 
where all land is cropped it is not convenient to employ this method during 
certain parts of the year, although it is usually possible to have one 
portion of the farm available for manuring at all times. 



/ 



CONTROL OF FLIES IN BARN YARDS AND PIG PENS 169 

The use of manure pits and boxes has been mentioned in a previous 
lecture, as has also the Hutchison maggot trap. It appears to the 
writer that any attempt to construct pits or boxes which are so tight 
as to prevent the escape of newly emerged flies is likely to meet with 
failure. In practically all instances the manure is infested more or 
less when placed in the box or pit, and following this suggestion the 
writer has been advocating the placing of the manure in boxes and pits 
which will not allow flies to gain entrance from the outside and which 
are provided with a cone or tent trap to capture the flies which breed out 
(see plate V). In the absence of the trap feature these would almost 
surely escape to the light from the most tightly constructed box or pit 
which it is feasible to build and maintain. A manure box of this 
type has been tried by the Dallas laboratory and found to work admir- 
ably. The number of flies caught is often surprisingly large. 

For small pastures and meadows it is sometimes feasible to utilize a 
brush drag to break up the cow droppings. This serves three purposes — 
preventing the breeding of the horn fly, scattering the manure evenly 
over the ground, and permitting the grass to grow where it would other- 
wise be prevented by the piles. 

While the house fly does not breed readily in pure cow manure the 
writer has reared the species from this substance and has also found 
that where cow manure is mixed with a certain amount of straw it is a 
fairly good breeding medium for this species. The horn fly, Lyperosia 
irritans (Haematobia) Linnaeus, breeds exclusively in cow droppings 
either in large piles or individual droppings. Blow flies are not known to 
breed in cow manure, but a number of species of Sarcophagids, most of 
which, however, do not have scavenger habits, breed in considerable num- 
bers. The brilliant green fly, Pseudopyrellia comicina Fabricius (plate 
III, fig. 4), is very commonly seen on fresh cow droppings; in fact this is 
usually the most abundant species in this situation in the country. It 
may be readily mistaken for Lucilia when not examined carefully. This 
species is of no importance as a human disease carrier as it does not 
enter houses or visit food. 2 

In preventing flies breeding in yards it is very essential that water 
troughs be kept from running over and whenever overflows or leaks do 
occur they should be fixed promptly and the moistened manure and earth 
cleaned up and hauled away immediately. Special attention should be 
given to accumulations of horse manure in yards along feeding racks. 
Here the mixture of horse manure, waste hay and urine forms a satisfac- 
tory mixture for fly production. 

2 Unquestionably its larvae must have an important role as regards organisms taken 
up from the manure and passed through their bodies, but whether this role is to destroy 
the organisms or to propagate and distribute is yet to be learned. — W. D. Pierce. 



170 SANITARY ENTOMOLOGY 

The use of larvicides and other chemical compounds in barn yards is 
usually inadvisable. Thorough cleaning ordinarily will handle the situa- 
tion. Crude oil has been used in yards where considerable numbers of 
horses are kept to permit firm packing of the ground and keep down 
dust in dry weather. Borax, either dry or in solution, may be used in 
breeding places which can not be cleaned thoroughly. Poultry and hogs 
consume large numbers of larvae and pupae and scatter the manure so it 
will dry out rapidly. These agencies should not be depended upon, how- 
ever, to effect control. 

The employment of conical fly traps about stables and dairy barns, 
if they are kept properly baited, will aid in reducing the number of house 
flies. Cheap molasses and water (1 to 3), or milk curd, brown sugar and 
water in equal parts form good baits. The latter, if kept moist, will 
remain attractive for two or three weeks. It is comparatively unattrac- 
tive for the first few da}^s. Hodge type window traps aid in reducing the 
house fly and stable fly troubles within barns if the barns are closely 
built and the other windows darkened or screened. 



FLY CONTROL IN PIG LOTS AND PENS 

The hog has been looked upon from time immemorial as a filthy ani- 
mal and he is usually compelled to live in surroundings which would never 
be tolerated for any other beast. 

One of the special problems which confronts the municipal and the 
army sanitarian is the utilization on a large scale of city and camp 
garbage by hog feeders. There appears to be no more economical way 
of disposing of garbage than by this method, but the conditions under 
which the feeding is to be done must be given strict attention by sani- 
tarians. In the vicinity of nearly every city and large army camp is 
located one or more of these garbage feeding plants, the number of hogs 
ranging from a few hundred to several thousand. For the most part the 
garbage is sold to feeders under annual contract. Army garbage at 
least is supposed to be free from glass, cans, coffee grounds, and liquids. 
The contractors furnish the garbage cans, remove the garbage daily and 
return empty cans which are supposed to be thoroughly cleaned. If the 
orange, grapefruit, and lemon peels could be eliminated from the garbage, 
the mass of material not eaten by the hogs would be materially reduced. 
Garbage feeding plants should be operated under approximately the 
following set of rules : 

1. Location of Feeding Stations. — Station should be located as far 
from habitations as possible and also well removed, two miles or more, from 
the city limits or the precincts of an army camp. Our recent experiments 
show that flies of various species, including the house fly, travel thirteen 



CONTROL OF FLIES IN BARN YARDS AND PIG PENS 171 



miles or more under rural conditions, but that there is a rapid decline 
in the number of flies which reach points two miles or more from the 
source of production. It is also desirable that the pens be located a 
considerable distance from main highways, as passing vehicles help to 
disseminate the flies. 

2. Drainage. — Adequate drainage is essential. It is preferable to 
have hog-feeding stations located on hilly ground and never on flat areas. 

3. Adequate Room. — In feeding garbage it is essential in order to 
maintain sanitary conditions that the hogs be given a considerable 
acreage. I would place this at a minimum of 225 sq. ft. per hog, or 
approximately 190 hogs to the acre. Of course as a general principle in 
fattening hogs it is considered necessary to reduce activity by close 
penning. It has been proven, however, that hogs make satisfactory gain 
when heavily fed if kept in large pastures. 



£ND VIEW 
OPEFf HOC-FEEDINCT/iOUCh 



Iroh-Roos - /rr Aranr 




Fig. 36. — Plans of open hog- feeding trough. (Bishopp.) 

4. Feeding Troughs and Platforms. — Concrete feeding troughs and 
platforms are essential under present inadequate labor conditions. A 
number of forms of troughs and platforms may prove satisfactory from 
a sanitary standpoint. In some cases feeding floors are used without any 
troughs but this necessitates daily cleaning. Under outdoor conditions 
such as exist in the South, it is advisable to locate the feeding troughs on 
land with pronounced slope. A simple form of construction consists of a 
concrete platform about 15 feet wide, length in proportion to number of 
hogs (fig. 36). This should have a backward slope of about 10 inches. 
The trough can be formed by setting a plank on edge in the concrete 
about three feet from the upper side and parallel with it or by a concrete 
ridge several inches high to form the lower edge of the trough. The 
upper edge of the platform should be raised so as to prevent water from 
washing into the trough and the feed racks to receive the garbage should 
be constructed over the front edge of the trough in such a way as to 



172 SANITARY ENTOMOLOGY 

receive all drip. The lower side should be provided with a concrete ridge 
projecting about five inches. This edge along the back will hold most 
of the unconsumed garbage, bones, etc., as they are worked backward, and 
facilitates thorough cleaning which should be done at not to exceed three- 
day intervals. 

5. Shade. — If location with plenty of trees can be chosen, this is 
preferable to sheds for protection from the sun. Where sheds are needed 
for protection either from sun or rain, they should be built on well drained 
land and never placed over the feeding troughs. They should be seven 
feet above the ground so as to permit of easy cleaning. Temporary 
shade can be constructed extending a few feet over the troughs if desired. 
6. Contracts. — Annual or longer contracts with the Ara^ or with 
municipalities are far more desirable than monthly contracts as they en- 
able the contractor to put up proper feeding facilities which he would not 
do under short contracts. Contracts should specify the character of feed- 
ing arrangements and penalize failure to keep the premises in satisfactory 
sanitary condition. The pens should be given frequent inspection by 
sanitary officers. 

7. Cleaning of Yards. — In addition to the cleaning of the uncon- 
sumed garbage from feeding platform the manure should be scraped up 
and disposed of, especially during rainy weather. During hot dry 
weather where ample pasturage is used manure is the source of very 
little fly trouble. 

8. Disposal of Bones. — Bones which are not retained on the feeding 
platform and those which are mixed with uneaten garbage should be 
collected at four-day intervals and placed in fly-proof bone racks. These 
can be built of lumber and screened on the outside and provided with 
fly-proof cover. It is desirable that the bones be removed entirely from 
the premises at frequent intervals. 

9. Avoidance of Transporting Flies on Vehicles. — If garbage cans 
are properly cleaned there is less tendency for flies to follow them than if 
left dirty. Washing in a moderately weak solution of cresol tends to 
repel flies from them. The trucks should be washed off occasionally. 
There is less danger of flies following trucks back to camps when they are 
provided with covers. 

10. Quantity Fed. — Feeding so much garbage to hogs that it will 
not be cleaned up should be discouraged. 

11. Final Disposal of Hog Manure and Unconsumed Garbage. — This 
material may be scattered thinly over cultivated ground and exposed 
to the sun or promptly plowed under. Where material is found to be 
heavily infested with maggots, it is advisable to dump it in piles some dis- 
tance from the feeding plant and treat it with borax solution. About one 
pound of borax should be used to each 8 bushels. If the mass is very wet 



CONTROL OF FLIES IN BARN YARDS AND PIG PENS 173 

the borax may be applied dry, but if the material will absorb liquid the 
borax should be dissolved in water at the rate of one pound to five 
gallons and sprinkled over it. 

12. Dead Hogs. — Dead hogs should be promptly disposed of either 
by burning on the ground or by hauling to rendering plants. 

13. Treatment of Hog Pens Where Flies Are Breeding. — All manure 
should be scraped up thoroughly, holes cleaned out and the ground 
sprinkled with borax solution made as above. The holes should then 
be filled and packed; crude oil will assist in this. Lime has little value in 
destroying fly maggots but will tend to dry up moist areas and reduce 
odor. Ringing the hogs' noses reduces the number of holes formed and 
is said to help keep them quiet in fattening. 

Fly Traps. — Each hog-feeding establishment should be provided with 
a number of well constructed fly traps, preferably of the conical type, 
and kept well baited. Black strap molasses and water at the rate of 1 
part molasses to three parts water may be used as bait, or 1 part dark 
brown sugar to 1 part vinegar and 3 parts water may be used. The traps 
should be set in situations where flies tend to congregate and away from 
danger of being disturbed. 

Hogs should not be tolerated in towns or cities. On. farms the same 
general rules for elimination of fly troubles should be followed as applied 
to garbage-feeding stations. For brood sows, good, dry, clean housing is 
essential from both the fly control standpoint and that of successful 
breeding. 

PREVENTION. OF FEY BREEDING IN CHICKEN HOUSES AND YARDS 

Comparatively little attention has been gfven to control of flies in 
poultry houses and yards. This source of fly breeding is one which should 
not be ignored as it is present even in far more premises than are manure 
piles from horses and cattle. Several species of flies breed in chicken 
manure, but the house fly, stable fly and lesser house fly seem to pre- 
dominate. The writer has found many cases in the South in which these 
species seemed to be passing the winter in chicken manure. This ap- 
pears to be a favorable place for the larvae to pass the winter as little 
heat is generated to hasten transformation and sufficient protection is 
afforded to prevent the destruction of the immature stages by cold. 

With small flocks of poultry in the back yard the prevention of fly 
breeding is not difficult but is very likely to be neglected. We have found 
that flies will breed in rather small accumulations of chicken manure on 
dropping boards but are produced in greatest numbers if the accumula- 
tions are on the soil itself. The weekly cleaning of all excrement from 
the dropping boards and floor is sufficient to prevent fly breeding. Usually 



174 SANITARY ENTOMOLOGY 

it requires more than a few days' droppings to produce a very favorable 
breeding situation. The cleaning of houses is of course facilitated by 
having the dropping boards readily removable or the roosts hinged so as 
to give free access to the boards. In the South, dropping boards are not 
being advocated and very few places are provided with them. In such 
houses a concrete floor is very desirable to make cleaning easy, but seldom 
found. Sprinkling the dropping boards or floors with air-slaked lime or 
dry sand helps to take up the moisture from the manure and reduce the 
attraction for flies. 

In small places where gardens are available chicken manure can be 
used to advantage as fertilizer. Where it cannot be disposed of in this 
way promptly it should be placed in a box under cover from rain and 
treated with borax as previously recommended. 

Dead fowls breed many dangerous species of flies and they should be 
disposed of promptly either by a scavenger wagon in a city, or by burning 
in rural districts. 

The care of yards and houses on large poultry farms should be 
handled in practically the same way as the small one just discussed. 
There is usually less trouble, however, from these large plants as they 
receive more constant attention than the small ones. Pigeonries are also 
a source of some fly breeding as the pigeon coops usually are placed in an 
inaccessible place and become very filthy. The houses should be made 
readily accessible and cleaned occasionally. Pigeons should be kept under 
control^ and porcelain dishes provided for nests will facilitate cleaning. 

The frequent and thorough cleaning up of the manure from all domes- 
tic animals and fowls tend to reduce the troubles among them from intes- 
tinal parasites. Spraying with standard disinfecting solutions has the 
effect of reducing the attractiveness for flies, of excrement, soiled floors, 
etc., in addition to the germicidal action. Cleanliness and spraying of 
premises also increase the efficiency of fly traps. 



CHAPTER XII 

Myiasis — Types of Injury and Life History, and Habits of Species 

Concerned 1 

F. C. Bishopp 

Myiasis is a term applied to" the attack of living man or animals by fly 
larva?. The medical profession usually assigns specific names to the 
infestations according to their location — as dermal (in or under the 
skin), nasal (nose infestation), auricular or otomyiasis (ear attack), 
intestinal, etc. These names are not entirely satisfactor}^ as often one 
form will develop into another or one species of larvae may be concerned 
in attacks in many different regions. And again several species may 
attack the same region but produce different types of injury, or the 
point of attack may vary with the stage of the larvae. 

Any attempt to classify the different types of myiasis according to 
character or place of attack or species of fly concerned seems to have 
its objections and difficulties. For convenience in discussion an attempt 
is made to divide the subject from the standpoint of method of attack 
into the following groups : 

First, TISSUE-DESTROYING FORMS, including those species 
which are ravenous feeders and destroy living tissues. For example the 
screw-worm, Chrysomya macellaria Linnaeus. The species which are 
included in this group with the exception of Wohlfahrtia magnified 
Schiner attack living animals secondarily, the main source of breeding 
being in dead animal matter. 

Second, SUBDERMAL MIGRATORY FORMS which are parasitic 
in animals or man and occur during the major part of their lives beneath 
the skin. For example, the ox warble, Dermatobia or "torcel," in 
man, etc. 

Third, LARVAE INFESTING THE INTESTINAL OR UROGENI- 
TAL TRACTS. These usually feed to a lesser or greater degree on food 
or excrementitious matter within the body. For example the larvae of 
the latrine flies of the genus Fannia and of certain flesh flies of the family 
Sarcophagidae. Infestations largely accidental, except horse bots and 
related species in animals which are truly parasitic. 

Fourth, FORMS INFESTING HEAD PASSAGES. True parasites 
1 This lecture was presented November 18 and distributed December 20, 1918. 

175 



176 SANITARY ENTOMOLOGY 

of animals or man occurring in the head sinuses, throat, or occasionally 
the eye. For example, the sheep bot, Oestrus ovis Linnaeus, and the deer 
bots, Cephenomyia spp. 

Fifth, BLOOD-SUCKING SPECIES. Highly specialized forms with 
blood sucking as a normal habit, exclusively parasites of man or animals, 
such as the Congo floor maggot attacking man, and larvae of the genus 
Protocalliphora attacking birds. 

Myiasis is caused by many species in several families. The habits, 
in regard to myiasis, of the species of any single family vary widely as 
might be expected in groups which have become more or less specialized. 
For instance, the family Oestridae, which is the only family having all its 
species concerned in myiasis, has members which infest the stomach, others 
which develop in the nasal passages and still others which produce 
cutaneous myiasis. The family Muscidae also exhibits very diverse habits 
in this regard, some members being concerned in destructive myiasis, 
others in specialized dermal cases and still others are blood suckers. 

Myiasis in animals is not generally considered in connection with 
human cases. There exists, however, a very intimate interrelationship ; 
in fact, the prevention of myiasis in man is largely dependent upon the 
control of the trouble in animals. Entomologists- engaged in sanitary 
work must be prepared to handle insect attack on animals as well as on 
man. 

Owing to the need for careful determination of the exact species con- 
cerned in cases of myiasis, both for the immediate needs of the case and for 
the benefit of science, it is highly desirable that the larvae concerned be 
bred to adults whenever possible. Specific determination of the larvae, 
especially when small, is, to say the least, very difficult, but a few should 
be preserved in alcohol for record and future identification when larval 
characters are better understood. Some suggestions as to breeding 
methods are apropos. There is no use endeavoring to rear Oestrids after 
extraction unless well matured. Most of the larvae from wounds will 
usually develop on beef. Care must be exercised in rearing the flies to 
avoid infestation of the material by other species, especially Sarcophagids 
which will drop larvae through screen wire onto meat or excrement. A 
double cage is best to- avoid this ; one of these should have a solid top. 
Good ventilation is important and sand slightly moist but not wet should 
be provided beneath the meat. The meat may be partially buried to 
retain moisture and reduce odor. It should be remembered that the 
larvae have a strong tendency to migrate when ready to pupate. 

TISSUE-DESTROYING FORMS 

It should be said that most forms of larvae attacking man or animals 
may destroy body cells to some extent but not in the sense of the rapid 



MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 177 

tearing away of tissues, as exhibited by species in this group. This is 
the most dangerous type of myiasis in man and one of the most important 
sources of loss due to insects among domestic animals. As previously 
pointed out, practically all the flies included in this group attack living 
animals as a secondary method of reproduction. 

It should be stated most emphatically that cases of myiasis, either in 
man or animals due to species in this group, are more or less intimately 
associated with violations of the best sanitary principles. The vast 
majority of cases of this type of nryiasis occur in the warmer parts 




Plate IX.— Carcass partly destroyed by larvae of the American screw-worm fly, 
Chrysomya macellaria. (Bishopp.) 

of the world. In the United States, as is well known, our principal source 
of trouble is due to the Muscoid fly, Chrysomya macellaria Linnaeus, 
commonly spoken of as the screw-worm (see plate I, fig. 3 ; plate II ; plate 
IX). Several other species are concerned to a greater or less degree, 
among these should be mentioned the black blow fly, Phormia regina 
Meigen (plate I, fig. 4), the green bottle flies, Lu cilia coesar Linnaeus 
(plate I, fig. 2) and L. sericata Meigen, certain of the flesh flies (Sarcoph- 
aga spp. (plate III, fig. 1) and occasionally some of the hairy blow- 
flies of the genera Cynomyia and Calliphora. 

Fortunately from the standpoint of the sanitary entomologist, the 
methods of control are in general very much the same for all species of 
this group, owing to the similar habits and not vastly different life his- 



178 SANITARY ENTOMOLOGY 

tories. All of the species, except Wohlfahrtia magnified Schiner, are 
carrion breeders although the adult flies are attracted to various kinds 
of food, especially those with strong pungent odors as come from the 
cooking of cabbage or turnips. A few develop occasionally in human 
excrement ; normally, however, the decomposition of animal matter has 
the strongest attraction for them and in many regions it is with great 
difficulty that animals can be slaughtered without having the meat 
contaminated by their presence in large numbers (see plate II). Garbage 
containing meat and bone will attract and breed them. 

America. — The screw-worm fly occurs throughout the United States, 
but is of little importance as a pest except in the Southwest where in 
some sections it is a veritable scourge to the raisers of livestock. 
The life history of this species will serve as an illustration for this 
group of flies in the United States. The eggs are deposited on carrion, 
especially on animals which have died recently. These hatch in a few 
hours into maggots which enter the tissues rapidly and become mature in 
about six to twenty days. In living animals development seems to be 
rather more rapid. Pupation takes place in the soil from the surface to 
three or four inches deep and the flies emerge in from three to fourteen 
days. The total development period from attack to adult has been found 
to vary from seven to thirty-nine days. The activity of this species is 
confined to the warmer part of the year, usually from about April first 
to November first in the Southern States. The black blow fly, Phormia 
regina, on the other hand, appears more resistant to cool weather and 
becomes most numerous in the southern region durmg early spring and 
late fall. This is also true to a large extent with the large hairy blow- 
flies. These latter entirely disappear during the summer months in the 
southern latitudes. 

Infestations of screw-worms in animals occur on any portion of the 
body where there is broken skin or even on sound skin where blood spots 
occur. For the most part, however, the infestations follow mechanical 
injury or where ticks have been crushed on the host. In man practi- 
cally any part of the body may be attacked, but the most common 
type of myiasis is nasal. This is especially true in Central and South 
America. Such infestations are usually associated with malignant 
catarrh or bleeding from the nose, and practically always with careless 
modes of living. The larvae enter the nose and penetrate the tissue, 
rapidly producing extensive cellulitis and usually accompanied by con- 
siderable serous or bloody discharge. If not detected for two days the 
injury is likely to be very serious. The frontal and ethmoid sinuses may 
be entered and the cartilage and even the bone attacked. Often the 
tissues of the nose and beneath the eyes begin to collapse and sometimes 
excavation reaches to the surface, giving permanent disfiguration. This 



MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 179 

extensive destruction of tissues often results in septicaemia or meningitis. 
Infestation of wounds on the battlefield or even in hospitals is not at all 
infrequent, but such cases are much more easily treated than nasal infes- 
tations. 

The black blow fly, Phormia regina Meigen, usually infests only old 
suppurating wounds. In livestock it is commonly found following dehorn- 
ing and has also been proved to be a common source of wool infestation 
of sheep in the Southwest. In the latter case the soiled wool following 
lambing attracts flies and the maggots feed on this for some time but 
later may enter the sheep itself and cause its destruction. 

The green bottle flies, Lucilia sericata Meigen and L. ccesar Linnaeus, 
which are commonly known as the wool maggots in the British Isles, 
occur throughout the United States. They have been known to infest 
wounds in man and animals but the main source of trouble has been the 
infestation of soiled wool on sheep. The method of attack in wounds is 
similar to that of screw-worms, but the tissue destruction is less rapid 
although this depends largely in either case upon the number of larvae 
present. They are more abundant in towns than in open country. 

In South and Central America and the West Indies, Chrysomya 
macellaria abounds and gives similar troubles to those in the United 
States. In Brazil, Sarcophaga lambens Wiedemann and S. pyophila N. 
& F. have been reported by Neiva and De Faria to infest wounds. In 
Hawaii Calliphora dux (Thompson) has caused considerable loss by 
attacking soiled wool and scabs on sheep. 

Europe. — In Europe the principal trouble from myiasis occurs in 
southern Russia. A considerable number of cases occur in the Mediter- 
ranean region and some farther north in Australia and Germany. In 
southeastern Russia, according to Portchinsky, the vast majority of cases 
of this type are caused by the flesh fly, Wohlfahrtia magnified Schiner, 
which appears to have habits of attack on man and animals very similar 
to that of the screw-worm fly in America. He speaks of its attack usually 
following wounds on the bodies of cattle, horses, pigs, dogs, and poultry. 
It also commonly infests the feet of animals suffering from foot-and- 
mouth disease. The cases in man occur most commonly in the nose, ears, 
and eyes. The injury is often serious, resulting in deafness, blindness, 
or facial disfiguration, and not infrequently in death. This fly deposits 
living larva?, and infestations in man are usually the result of sleeping 
outdoors during the warm part of the day. The fly is most abundant 
in nelds and woods rather than in towns. It is said to breed in living 
animals only, thus differing in an important respect from the screw- 
worm fly. 

While this species is not commonly spoken of as a pest in western 
Europe, Liitje reports considerable trouble from it in the western war 



180 SANITARY ENTOMOLOGY 

theater, especially during 1915. It infested wounds and interfered with 
their proper treatment and also was responsible for many infestations 
of the genitalia of cows in that region. 

Next in importance comes the flesh fly, Sarcophaga carnaria Linnaeus. 
This form does not seem so prone to attack living animals as Wohlfahrtia 
magnified Schiner, but there are numerous cases of myiasis in old sup- 
purating sores. These may occur in any part of animals or man. In the 
Petrograd district Lucilia caesar Linnaeus is responsible for some cases of 
myiasis, while in Denmark, Holland, and parts of Germany and France, 
L. sericata Meigen is concerned in the infestation of wounds. Calliphora 
erythrocephala Meigen, Musca domestica Linnaeus and Muscina stabu- 
lans Fallen (plate III, fig. 2) are said to oviposit on corpses on the battle- 
field soon after death but before putrefaction sets in. 

The larvae of Anthomyia pluvialis Linnaeus has been reported as being 
concerned in auricular myiasis. Probably this species should be con- 
sidered as a feeder on excreta rather than placed with tissue-destroying 
forms. 

Africa. — Wohlfahrtia magnifica Schiner is reported by Gough in 
Egypt as being taken from ulcers behind the ears and from orbits of 
patients in the ophthalmic hospitals. In tropical Africa Lucilia argyro- 
cephala Wiedemann commonly attacks mammals, man, and birds. Mem- 
bers of the genus Pycnosoma, which has been included with Chrysomya 
by some authors, cause myiasis in numerous caases. Pycnosoma megaceph- 
ala and P. bezziana Vill. are frequently mentioned in literature in con- 
nection with cases of myiasis in cattle, horses, camels, and other animals, 
as well as man. P. putorium Wiedemann, P. marginale Wiedemann and 
Chrysomya chloropyga (Wiedemann) Townsend are also concerned. 
Sarcophagids have been recorded as infesting wounds ; S. haemorrhoidalis 
Fuller and S. regularis Wiedemann being mentioned in particular. 

Asia. — While there are numerous references to myiasis cases in Asia, 
our knowledge of the species concerned is limited. Members of the genus 
Pycnosoma, particularly P. flaviceps Walker, are concerned with cases in 
India. This species and Lucilia serenissima Fabricius have been men- 
tioned particularly as being troublesome by attacking cattle after out- 
breaks of foot-and-mouth disease. It is possible that they may be con- 
cerned with the spread of this disease in addition to the injury wrought 
by their burrowing into the tissues. The cosmopolitan Lucilia cazsar 
Linnaeus is responsible for some cases of myiasis. Several Sarcophagidae 
have been reported as causing nasal myiasis of man in parts of India, but 
most of these have not been specifically determined. S. ruficornis 
Fabricius seems to be among those most frequently concerned. 

Australia. — While reports of destructive myiasis in man are com- 
paratively few from Australia, certain parts are subjected to veritable 



MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 181 

plague of myiasis among sheep. The center of the region where this 
scourge occurs is in New South Wales, where work for the commonwealth 
government has been carried on by Professor W. W. Froggatt for several 
years. Only a brief mention of the species concerned and the character 
of attack can be given. 

The loss is brought about through the blowing of the soiled wool, 
particularly around the vents of the ewes. The infestation, if not 
promptly treated, spreads forward in the wool, resulting in a large loss in 
the clip and often the larvae gain entrance to the bodies of sheep and 
cause their death. Even though penetration does not occur, the skin is 
acutely inflamed and gives rise to fever, loss of appetite, and sometimes 
death. Froggatt states that he has bred 1,050 flies from the maggots in 
one pound of wool. 

Froggatt holds that the blowing of wool is largely an acquired habit 
on the part of Australian flies, as practically no cases of this kind were 
noted up to 1903 or 1901. He attributes the acquisition of this habit to 
the extended drought which destroyed large numbers of animals of all 
kinds and resulted in the production of myriads of flies. He thinks that 
during this period Several species of flies acquired the habit of depositing 
in "smelly" wool. He also considers the more extensive breeding of heavy 
wooled sheep to be a contributory factor. It is certain that injury from 
blow-flies has developed from an almost unnoticed trouble to a problem 
of first magnitude within the space of a few years. During the first 
few 3 T ears of the acute trouble the small yellow house fly, Anastellorhina 
augur Linnaeus, and the golden hair blow-fly, Neopollenia stygia 
(Fabricius) Townsend (Pollenia villosa Robineau-Desvoidy) appeared 
to be the principal culprits. In 1913, when the work was taken up more 
extensively it was found that the "green and blue" sheep maggot fly, 
Chrysomya rufifacies Macquart (Pycnosoma), was assuming first impor- 
tance in connection with the infestation of sheep. The difference in 
apparent injuriousness is probably governed largely by the seasonal 
conditions as in the case of species in our own country, C. rufifacies appar- 
ently being concerned largely with cases of m} r iasis in summer and A. 
augur during the cool weather. The life histories of these flies do not 
differ materially from that of the screw-worm fly, the life cycle being 
completed in about two weeks under favorable conditions. Other species 
which have been bred from wool in Australia are Microcalliphoi'a varipes 
(Macquart) Townsend, the Anthomyid, Ophyra nigra Wiedemann, 
Sarcophaga aurifrons Macquart, and the cosmopolitan Lucilia sericata 
and L. cazsar, and possibly L. tasmaniensis. 



182 SANITARY ENTOMOLOGY 



SUBDERMAL MIGRATORY SPECIES 



The species concerned in this form of myiasis are truly parasitic. 
In the cases of man they can not be considered as especially dangerous, 
but in animals they assume first rank as destructive parasites. 

The type of myiasis produced by these larvae is described under 
various names in medical literature but especially mentioned as creeping 
disease. This is owing to the movement of the larvae in the subcutaneous 
tissues. In the United States we have little concern for cases of myiasis 
in man produced by this group of flies as they are comparatively infre- 
quent. The species concerned are Hypoderma, probably mostly Imeata 
DeVillers and Gastrophilus, probably mostly intestinalis DeGeer (plates 
X, XII). Unfortunately the larvae concerned usually have not been 
preserved, and in a very few cases have any larvae from man been reared 
to maturity. 

The sanitary entomologist is not particularly concerned with the 
Oestrids infesting cattle, but on account of their importance to the 
veterinary entomologist they are here briefly discussed (see plates XI, 
XIII). There are two species in this country, H. lineata De Villers and 
H. bovis DeGeer. The former is the predominant form in the United 
States, especially in the southern three-fourths of the country, while the 
latter is more restricted to the northern tier of States, New England and 
Canada. The adults are known as heel flies and oviposit on the hairs, prin- 
cipally on the legs of cattle. These eggs hatch in three or four days and 
the larvae penetrate the skin at the point of attachment or in some 
instances may be taken in by licking. After several months spent in the 
body of the animal they appear during the late fall and winter months 
under the hide along the back, forming subcutaneous tumors. When full 
grown these grubs emerge from the host, drop to the ground and after 
about twenty-five to thirty-five days spent in the pupal stage produce 
flies which are ready to attack cattle the first warm days during spring. 

Several cases have recently come under the observation of Mr. E. W. 
Laake and the writer of the occurrence of this species in the backs of 
horses. These are responsible for the production of lesions which prac- 
tically render the use of the infested animals as saddle horses impossible 
for a few weeks. 

There are a number of records of the occurrence of the young larvae 
of these flies in man, especially children. Attention is usually first called 
to them on account of pain, soreness or itching in the region of the 
shoulders or face. The irritation is sometimes rather acute and its 
location moves with the burrowing of the larvae. Before becoming mature 
the grubs appear near the surface under the skin or beneath the mucous 
membranes of the mouth and can there be extracted with ease. 



MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 183 




Plate ^X. — Horse bot flies. Fig. 1 (upper). — Gaslrophilus intestinalis, the common 
bot. Fig. 2 (lower). — Gastrophihis haemorrhoidalis, the nose fly. (Dove.) 



184. 



SANITARY ENTOMOLOGY 





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Plate XT. — Phases of the life cycle of bot flies. Fig. 1 (upper right). — Empty eggs 
of the cattle bot, Hypoderma lineata. Fig. 2 (upper left). — Eggs of the common 
horse bot, Gastrophilus intestinalis. Fig. 3 (center). — Full grown larva of Hy- 
poderma lineata. Fig. 4 (lower right). — Empty puparium of Hypoderma lineata. 
Fig. 5 (lower left). — Empty puparium of Gastrophilus intestinalis. (Bishopp.) 



MYIASIS— TYPES OF INJURY. LIFE HISTORY. HABITS 185 




Plate XII. — Method of attack by the common horse bot, Gastrophihts intestinalis. 
Fig. 1 (upper). — Eggs on horse's legs. Fig. -2 (lower). — Larvae attached to walls 
of stomach, showing lesions caused by removed bots in center. (Bishopp.) 



186 



SANITARY ENTOMOLOGY 




Plate XIII. — Method of attack by the cattle bot, or heel fly, Hypoderma lineata. Fig. 
1 (upper right). — Fly ovipositing on cow's leg. Fig. 2 (upper left).— Portion of 
cow's back showing larvae, empty holes and pus exudate. Fig. 3 (lower).— Heav- 
ily infested cow. (Bishopp.) 



MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 187 

These infestations probably come about through the accidental 
depositions of eggs on the bodies or clothing of man, especially children. 
The possibility of this method of infestation is emphasized through the 
experience of Dr. Glaser, who while studying ox warbles in Germany had a 
fly deposit an egg on his trousers which in due time hatched and the 
young larva penetrated the skin of his leg. Later its presence in the 
oesophageal region was detected by an uncomfortable feeling. The larva 
apparently passed up the oesophagus and later was extracted at the 
base of one of the molar teeth. 

In instances where the Oestrid fly of the genus Gastrophilus attacks 
man the conditions surrounding the infestation as well as the exact 
identity of the larva are less well understood. It is supposed that the 
young larvae are in some way brought in contact with the mucous mem- 




Fig. 37. — Full grown larva of the human bot, Dermatobia hominis. (Drawing by 
Bradford.) Actual length 14.5 mm. 

branes of the lips, mouth or eyes and penetrate them, later appearing 
under the skin and moving about in a manner somewhat similar to 
Hypoderma. The life history of the species of this genus will be dis- 
cussed under intestinal myiasis. 

America. — In America in addition to the Hypodermas we have among 
the lower mammals dermal myiasis produced by several different species 
of Oestrids in the genus Cuterebra. These are most commonly met with 
in rabbits, squirrels and certain field mice. Usually they appear to cause 
no serious injury except in the case of one form, which is prone to 
attack the testicles of squirrels and was given the name of Cuterebra 
emascvlator Fitch (equals C. fontinella Clark). 

In South America a very interesting and more important form of 
myiasis in man occurs. This is produced by the Oestrid, Dermatobia 
homvnis (Carl Linne, Jr.) (noxialis Goudot, cyanwentris, Macquart) 
(fig. 37). This form appears to be normally the parasite of cattle, horses, 
donkeys and certain wild animals. It is reported as being a serious pest 



188 SANITARY ENTOMOLOGY 

of cattle, in some cases causing the death of many calves, especially when 
the cutaneous tumors become infested with larvae of Chrysomya. 

The life history and habits of the species have not been fully eluci- 
dated, although a number of important contributions have been made. 
It is generally concluded that the infestation of man is brought about in 
the following indirect but very interesting manner: The eggs of the fly 
are deposited on the bodies of certain bloodsucking insects, especially the 
mosquito known as Psorophora Iwtzi Theobald (Janthinosoma), or 
attached to leaves frequented by these insects whence they adhere 
to them. The eggs are attached vertically on the under side of the 
abdomen or the legs. The embryos appear to remain dormant though 
fully developed within the egg and when the bloodsucking dipteron 
finds a host, the heat of the animal or the blood taken up stimulates the 
larvae to break from the shell and penetrate the skin of the host. Dermal 
tumors are formed by the larvae, a well-marked hole opening to the outside 
as in the case of the ox warble. When the grubs become full grown they 
leave the host, drop to the ground and transform to adults. The period 
in the host ranges from two to six months. During this time there is 
more or less inflammation and sometimes acute pain. This form is widely 
distributed through tropical America. Lieut. L. H. Dunn has recorded 
cases of apparent transmission of the eggs by ticks. 

In South America Dr. J. C. Nielson has reported the occurrence of the 
Anthomyid flies (Mydaea anomala and M. torquens) as producing subcu- 
taneous tumors in various birds in parts of Argentina, and Dr. C. H. T. 
Townsend records M. spermophilae as parasitic on nestlings in Jamaica. 

Europe. — Several cases of dermal myiasis have been reported, espe- 
cially from Russia. These are attributed to infestations of larvae of 
Hypoderma and Gastrophilus. 

The infestation of reindeer in Lapland and farther south in Norway 
by larvae of the Oestrid fly, Oedemagena tarandi Linnaeus, should be 
mentioned. The infestations are almost analogous to those in cattle 
caused by Hypoderma. The eggs are laid on the hair during the spring 
and later the larvae appear in the submucous tissues of the back. As 
many as 300 have been reported as occurring in a single animal. This 
same species no doubt infests the reindeer in Alaska and Canada. 

Africa. — In Africa the outstanding form of dermal myiasis is pro- 
duced by the Muscid fly, Cordylobia anthropophaga Griinberg, commonly 
spoken of as the Tumbu fly (figs. 38, 39). The larvae are known as "Ver 
du Cayor." These develop in the skin of man and various other hosts 
including dogs (probably the preferred host), cats, horses, and other 
domestic and wild animals. The attack is painful but not serious, though 
no doubt when numerous specimens are present unpleasant symptoms fol- 
low. The life history of this form has not been entirely elucidated, but 



MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 189 

it is generally believed that the eggs are deposited on the ground in places 
frequented by hosts and the larvae hatch and penetrate directly through 
the skin. In some cases it appears that eggs have been deposited on 
clothing, especially if moist with perspiration. They appear in March 




Fig. 38. — Full-grown larva of the Tumbu-fly (Cordylobia anthropophaga, Grunberg). 
Ventral view. X 6. (From Austen.) 




d& 




Fig. 39. — The Tumbu-Fly (Cordylobia anthropophaga, Grunberg). Female. X 6. 

(From Austen.) 

and diminish until some time in September when they entirely disappear. 
Experiments conducted by Roubaud indicate that the choice of host 
depends mainly on body temperature, the high temperature of hogs and 
fowls being fatal to the larvae. 

Cordylobia rodhaini Gedoelst is the cause of cutaneous myiasis in the 



190 SANITARY ENTOMOLOGY 

forest regions of Africa. Man is an accidental host, the species normally 
infesting thin skinned wild mammals. According to Rodhain and 
Bequaert, who have given much attention to the biologies of this and 
related species, the eggs are deposited on the ground in the burrows fre- 
quented by the animals, the larvae hatch out and penetrate the skin when 
the hosts are lying upon them. The larvae develop within the host in 
twelve to fifteen days. The pupal stage, which is passed in the ground, 
ranges from twenty-three to twenty-six days, the life cycle being about 
forty days. Another Muscid genus, Bengalia (especially B. depressa 
Walker) , causes cutaneous myiasis in man in Rhodesia and other parts of 
Africa. The eggs are deposited on the clothing or person of man and 
on the hair of animals. 

Another interesting form is Neocuterebra squamosa Grunberg, which 
develops in the adipose tissues in the soles of the feet of the African 
elephant. 

INTESTINAL AND UROGENITAL MYIASIS 

There is every reason to believe that myiasis of the intestinal tract 
and urogenital openings results largely from careless modes of living. 
The types of myiasis included in this group should not be confused with 
urogenital myiasis caused by Chrysomya and related forms. A large per- 
centage of these cases is purely accidental and there is no doubt that a 
great many larvae are ingested with food which never produce symptoms 
to attract attention to their presence. Several different families of flies 
have been recorded as causing intestinal myiasis, one of the most com- 
mon being the rat-tail larvae of the family Syrphidae. Records of intes- 
tinal myiasis due to Sarcophagidae are also numerous, but it should be 
borne in mind, especially with this fly, that there are many opportunities 
for mistakes. With little doubt, in many instances, the larvae are not 
passed, but are deposited in the excrement by flies which have the habit of 
visiting and depositing larvae almost instantly after defecation. 

The whole group may be subdivided into those forms which are directly 
parasitic, such as horse bots, and others which are more or less acci- 
dental. 

America. — The importance of the horse bots in infesting equines is 
such that brief discussion is necessary. In this country there are three 
species, all of which are of considerable economic importance. These are 
the common horse bot, Gastrophilus intestmalis DeGeer, the chin fly or 
throat bot fly, G. nasalis Linnaeus and the nose fly, G. haemorrhoidalis 
Linnaeus (plates X, XII). These three species are widely distributed 
throughout the world and were met with as pests in many of the recent 
war theaters. Certain other species are also present in European and 
Asiatic countries but these are of less importance. 



MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 191 

The life history of the common bot fly is about as follows : The eggs 
are attached to the hairs of the host, mainly on the legs, but frequently 
on other parts. These are ready to hatch in from nine to forty days. 
The larva? are removed from the eggs by the biting and licking of the 
host. They take up their abode in the stomach, remaining attached to the 
mucous coatings of the pyloric end of this organ until fully grown sev- 
eral months later. They then detach and pass out with the manure, 
pupate near the surface of the ground and produce the so-called bot flies 
three to six weeks later. The cycle is completed in about a year. The 
life histories of the nose fly and throat bot are similar but differ especially 
in the method of oviposition. The former deposits its eggs, which are 
nearly black, on the very minute hairs around the lips. The young larvae 
gain access to the mouth and develop as in the common bot fly, but before 
passing out they usually catch hold of the mucous membrane of the 
rectum and are often seen protruding from the anus a few days before 
dropping. The annoyance produced by the oviposition of this fly is 
very severe. The throat bot deposits its eggs mainly under the jaws and 
the larvae are often found in the duodenum and also attach in the stomach. 

In addition to the annoyance produced at the time eggs are deposited, 
heavy infestations in the stomach interfere with digestion and cases are 
recorded where the larvae caused death by stopping the pyloric opening. 
The irritation of bots, which may be present in numbers exceeding 1,000, 
must be detrimental to the host. The throat bot also attaches in the 
pharynx in its early stages and is accredited with causing the death of 
animals from this habit. 

Cases of dermal myiasis in man attributable to these species have 
already been mentioned. European writers have also reported the occur- 
rence of larvae of Ga strophulus in the eye of man. 

Passing to those forms which are more or less accidental, the Sar- 
cophagidae demand first attention. Hasseman has reported a case in 
which an entire family was infested with the larvae of Sarcopliaga liaemor- 
rhoidalis, the maggots being passed in considerable numbers during warm 
weather. Numerous other similar instances have occurred and in prac- 
tically every instance they are traceable to leaving foods exposed to flies 
between meals. Since the Sarcophagids deposit living larvae on meats, 
etc., they may be easily overlooked. 

Cases of intestinal myiasis due to Eristalis larvae are common in this 
country. A good summary of these cases has been made by Hall & Muir. 
It appears that they sometimes give rise to acute colicky pains but no 
serious symptoms. As is well known, the rat-tail larvae are to be found 
in decaying vegetation and in water, and the source of infestation must 
be through the swallowing of uncooked and poorly cleaned food such as 
watercress and lettuce, and the drinking of unclean water. The follow- 



192 SANITARY ENTOMOLOGY 

ing species have been recorded in this connection : Eristalis tenax Lin- 
naeus, E. arbustorum Fabricius, E. dimidiatus Wiedemann, and Heloph- 
ilus pendulinus Meigen. 

The cheese maggot or skipper Piophila casei Linnaeus, is referred 
to in a number of instances as the cause of intestinal myiasis, often pro- 
ducing intense colic, and this form has also been recorded from the nose. 
On account of the common habit of this fly of depositing its eggs in 
cheese and smoked meat, it is no doubt often eaten in considerable num- 
bers and the cases where it gives trouble must be comparatively few. 
This insect passes its complete life cycle in the foods mentioned above, 
usually attaining the adult stage in about three weeks. It is world-wide 
in distribution. 

Species of Muscina, especially M. stabulans Macquart, have been met 
with frequently in cases of intestinal myiasis, especially in Europe. 

Mydcea vomitwrationis Robineau-Desvoidy is charged with a case of 
fatal intestinal myiasis. 

Hydrotaea meteorica Linnaeus, a fly probably normally predaceous in 
the larval stage, has been found to produce intestinal myiasis, in which 
case blood is sometimes passed accompanied with severe pain. 

Larvae of the common house fly have been passed in living condition, 
sometimes preceded by pain. Most of these cases have been in infants 
and the larvae no doubt usually gain access through the anus. These 
cases usually result from improper care. 

The cluster fly, Pollenia rudis Robineau-Desvoidy of the family 
Muscidae, has been reported in a case of intestinal myiasis. It is difficult 
to see how this form could gain access to the human alimentary tract since 
it is normally found only as a parasite of earthworms. 

In certain parts of tropical America and the West Indies, India, Cey- 
lon, and the Malay States, the small Phorid, Aphiochaeta ferruginea 
Brunetti, has been found infesting the human intestinal canal in many 
instances. Brunetti states that specimens of this fly were sent to the 
Indian Museum by Crombe with a statement that "eggs, grubs, and flies 
were all voided together." This occurrence, together with observations 
made by Baker and reported by Austen, indicate that the flies are capable 
of living and depositing eggs in the human intestines. This is also sub- 
stantiated by the fact that larvae of this fly may be passed with excre- 
ment for as long as a year with symptoms similar to those of beri-beri. 
Other members of the family Phoridae have been found in human corpses 
buried for two or more years ; living larva 1 , pupae, and adult flies being 
found together. Aphiochaeta ferruginea breeds in excrement and often 
frequents various foods including fresh meat. It also breeds in carrion. 
Its small size enables it to pass through ordinary screen wire and thus 
increases its potentialities for producing disease. 



MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 193 

The Anthomyid flies of the genus Fannia have been recorded as caus- 
ing serious gastric disorders. Among the symptoms are abdominal pains, 
nausea, and vomiting, and sometimes vertigo, headache, and bloody diar- 
rhea. Fannia canicularis (plate VII, fig. 3; text figs. 14-16), commonly 
called the lesser house fly, and Fanma scalaris (text figs. 17-19) are 
widely distributed and breed in various types of decaying vegetable mat- 
ter and excrement. We find that the larvae will feed upon and penetrate 
meat, and the} 7 may attack the living tissues to some extent. 

In the urogenital infesting group the above-mentioned species of 
Fannia, which are also known as the latrine flies, figure most prominently. 
These species are rather strongly attracted to human excrement, espe- 
cially urine. This habit is undoubtedly responsible for the infestation 
of the genitalia. Such infestations must certainly be attributed to the 
exposure of the genitals in sleep by drunken or careless persons, or occa- 
sionally infants. Robineau-Desvoidy has reported a case in which an 
Oestrid larva was passed from the bladder by a woman. Kollar has re- 
ported the occurrence of a large number of larvae of the common house 
fly in the vagina of a diseased woman. Chevral has brought together 
a number of records of cases of myiasis of the genitalia. 

Europe. — Nearly all the above-mentioned forms are to be encoun- 
tered in parts of Europe. In the Mediterranean countries one would 
expect to find a greater number of forms leading to these types of 
myiasis. 

Africa. — Several of the previously mentioned forms occur in Africa. 
The Oestrid larva, Pharyngobolus africanus Brauer, commonly attaches 
to the walls of the esophagus of the African elephant, and an Oestrid 
of the genus Cobboldia (C. loxodontis Brauer and C. chrysidiformis 
Rodhain and Bequaert) are found in the stomach of the African ele- 
phant, and C. elephantis (Steel) Cobbold, attacks the Indian elephant in 
a similar way. Species of Girostigma in the same family infest the 
stomach of the Rhinoceros. Antliomyia disgordiensis is said to be not 
infrequently passed from the intestines of man in Angola. 

FORMS PRODUCING MYIASIS IN HEAD PASSAGES 

All of the species included in this group are normally parasitic on 
animals, and infestation of man, although not uncommon, must be con- 
sidered accidental. In the lower animals the attack of these larvae is 
often quite injurious though not usually fatal in itself. In man the 
principal injury sustained is in the effects on the eye when it happens to 
be attacked. 

America. — In the United States as well as in all parts of the world, 
the sheep head maggot, Oestrus oris Linnaeus, is the most important 



194 SANITARY ENTOMOLOGY 

form in this group. The fly deposits living larvae on the nose of the 
sheep and the young maggots work upward through the nasal passage, 
later entering the head sinuses. The maggots are quite spiny and hence 
must produce much irritation. They appear to subsist upon the mucous 
secretions of the head cavity. Several months are passed in the host 
and the larvae drop out and pupate in protected places on the ground, 
producing flies a few weeks later. 

I know of no record of the attack of man by this species in the 
United States, but in other countries it frequently attacks the eyes, 
nose, mouth, and ears. The fly deposits the larvae so quickly that there 
is little opportunity to protect one's self. The most serious symptoms 
develop from infestation of the eye where larvae produce severe conjunc- 
tivitis and in some cases, if not promptly removed, cause the loss of 
sight. 

In this country the Cervidae (deer, elk, etc.) are attacked by Oestrids 
of the genus Cephenomyia (C. pratti Hunter, and C. phobifer Clark). 
The larvae of these flies are found in the head passages, pharynx, and 
even in the lungs. 

Europe. — The sheep head bot has a wide distribution in Europe 
and is responsible for loss among sheep and infestation of man as above 
described. 

Probably the most important species in this group is Rhinoestrus 
purpureus Brauer, which is a very common parasite of the horse in 
Russia, Hungary, and Italy. This form is also responsible for cases 
of myiasis in the eyes of man, the attack apparently being similar to that 
of Oestrus ovis. Horses are infested by the flies which deposit larvae 
in the nose or eyes. They are much annoyed by the deposition of the 
insect and the larvae give rise to fits and other symptoms, mistaken for 
strangles, sometimes resulting in death. The species is also known to 
attack the zebra. Cases of the occurrence of this species in the eyes of 
man have been reported from Jerusalem, and are not infrequent in 
southern Russia. 

The reindeer in Europe are subject to the attack of Cephenomyia 
trompe Linnaeus in a way similar to the infestation of sheep by Oestrus 
ovis. Nativig reports the finding of as many as 100 larvae in the nasal 
cavity and larynx of a young reindeer. 

Africa. — In Algiers, especially, Oestrus ovis is very destructive to 
sheep and many cases have been reported by the Sergents and others of 
the infestation of man by this species. The horse head bot, Rhinoestrus 
purpureus, occurs in the Egyptian region. The camels are infested by 
the Oestrid, Cephalomyia maculata Wiedemann {Cephalopsis titillator 
Clark). Larvae thought to be Rhinoestrus nasalis are common in the head 
sinuses of cattle in parts of Africa. 



MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 195 

Many species of Oestrids occur in the head passages of African 
animals. Rhinoestrus hippopotami Griinberg occurs in the skulls of 
hippopotami and apparently this species attacks hogs. The genera 
Gedoelstia and Kirkioestrus each contain species which infest the head 
sinuses of African wild mammals. 



BLOODSUCKING FORMS 

This mode of attack is not generally considered myiasis but it seems 
to haye a logical place in this discussion. All of the species haying 
bloodsucking habits developed among their laryae are to be found in 
the family Muscidae. Up to the present time there seems to be com- 
paratively little importance attached to them, although such forms as the 
Congo floor maggot may be responsible for the introduction of disease 
germs into man. 

America. — The only representatives of this group found in North 
America are Phormia azurea (Fallen) Villeneuve and P. chrysorrhoea 
(Meigen) Rodhain and Bequaert. The first mentioned species is found 
commonly in Europe where it was first recorded as feeding in the larval 
stage on nestlings of the sparrow and other birds. This same habit 
has been observed in the United States. The second form, which is quite 
common in the nests of larks and other birds in the southwestern states, 
appears to cause a definite dermal myiasis as the larva? are frequently 
found partially imbedded in the wings, legs and body tissues of fledglings. 
The fly, Mydaea pici Macquart, is reported as infesting young birds in a 
similar way in Brazil. 2 

Europe. — Phormia azurea (above mentioned) is quite common in the 
nests of birds in France and P. sordida (Zetterstedt) Roubaud has similar 
habits. 

Africa. — The form which is especially interesting and important 
in this group is the African floor maggot, Auchmeromyia hiteola (Fab- 
ricius). This fly appears to be very closely associated with man. The 
adults are found in the dwellings and about latrines in tropical and 
sub-tropical Africa. The eggs are deposited on the dry soil of the floors 
of native huts, especially under sleeping mats. The larvae come out at 
night and attack the sleepers, filling with blood in a very short time. 
The adult is also a blood-sucker. The larval stage occupies about fif- 
teen days and the pupal stage about eleven days. The larvae do not 
burrow into the tissues but simply attack the skin with the mouth hooks 
and suck the blood. 

2 Plath has reported recently on the occurrence in the nest of a robin larvae of a 
new species, Phormia metaUica Townsend. He also discovered in birds' nests, larvae 
of a new species of Anthomyidae, Hylemyia nidicola Aldrich. The latter probably 
feeds on dead birds onlv. 



196 SANITARY ENTOMOLOGY 

The related genus Choeromyia contains three or four species includ- 
ing C. choerophaga Roubaud and C. boueti Roubaud which occasionally 
bite man but normally live in the burrows of such hairless animals as 
the warthog and ant bear. The habits are similar to the floor maggot. 

Certain birds are attacked by the larvae of Passeromyia heterochaeta 
Villeneuve in a way similar to that reported for Phormia. This form 
occurs in Central Africa and also in China. 



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198 SANITARY ENTOMOLOGY 

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Rodhain, J., and Bequaert, J., 1916. — Materials for a monograph on 

the parasitic Diptera of Africa. Second Part. A revision of the 

Oestrinae of the African Continent. Bull. Sci. France et Belgique, 

Ser. 7, vol. 50, Nos. 1-2, pp. 53-165, 29 figs., 1 pi., November 

25. 
Rodhain, J., and Bequaert, J., 1919. — Materials for a monograph on the 

parasitic Diptera of Africa. Third Part. Bull. Sci. France et 

Belgique, vol. 52, No. 4, pp. 379-465, 21 figs., 3 pis. 
Roubaud, E., 1913. — Researches on Auchmeromyia, Calliphorine flies 

with blood-sucking larvae from tropical Africa. Bull. Sci. France 

et Belgique, Ser. 7, vol. 47, fasc. 3, pp. 105-202, 2 pis., 32 figs., 

June 24. 
Roubaud, E., 1914. — Stomach- and sinus-inhabiting Oestrids of French 

West Africa. Bull. Soc Path. Exot., vol. 7, No. 3, pp. 212-215, 

March 11. 



MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 199 

Roubaud, E., 1914.— Studies of the parasitic fauna of French West 

Africa. Part I. The producers of myiasis and similar disorders in 

man and animals. Paris : Masson & Co., 251 pp., 4 col. pis., 70 

figs. 
Roubaud, E., 1915. — Muscids* the larvae of which bite and suck blood. 

C. R. Soc. Biol., Paris, vol. 78, No. 5, pp. 92-97, 2 figs., March 

19. 
Sambon, L. W., 1915. — Observations on the life history of Dermatobia 

hominis. Rept. Adv. Com., Trop. Diseases" Research Fund for 1914, 

London, pp. 119-150. 
Sergent, Ed., and Sergent, Et., 1913.— "Tamne"— the "Thimni" of the 

Kabyles — the human myiasis of the Taureg Mountains in the Sahara, 

caused by Oestrus ovis. Bull. Soc. Path. Exot., No. 7, pp. 487-488, 

July 9. 
Ward, Henry B., 1903. — On the development of Dermatobia hominis. 

Rep. from the Mark Anniversary Volume, Article XXV, pp. 483-512, 

plates 35-36. 



CHAPTER XIII 

Myiasis — Its Prevention and Treatment * 
F. C. Bishopp 

In the preceding lecture the habits and biologies of the various species 
concerned in myiasis in man and animals have been briefly outlined. 
An accurate knowledge of the species concerned and a good general idea 
of its biology and habits are essential to the proper handling of myiasis, 
especially when the cases are numerous. 

In discussing control of the flies concerned and the treatment of cases 
the same general grouping as made in the previous lecture will be fol- 
lowed. Where various species of Mow flies and delated forms are 
numerous, immediate steps should be taken to determine the source of 
supply and energetic measures applied to prevent it without waiting for 
the appearance of cases of myiasis in man or animals. 

TISSUE-DESTROYING FORMS 

Prevention of Breeding. — Since practically all species concerned in 
the production of this form of myiasis develop within decaying animal 
matter, first attention must be given to this point. 

Burning of Carcasses. — The carcasses of large animals are sources 
of tremendous numbers of flies. We have estimated that over a million 
specimens may be produced in the body of one cow. Nothing is as satis- 
factory as complete destruction of carcasses by burning. This not only 
prevents fly breeding but reduces the chances of the propagation of 
such diseases as black-leg, anthrax and tuberculosis. Carcass burning 
can be carried out under practically any condition with which the sani- 
tary entomologist will have to deal and the process is by no means 
difficult nor expensive. Various methods have been advocated but we have 
found nothing equal to the following: Dig a trench about eighteen 
inches wide, twelve or fourteen inches deep and equal to the length of 
the carcass to be burned (plate XIV). This trench should be dug with 
the direction of the prevailing wind and along the back of the car- 
cass ; fill the trench with wood and then turn the animal over on top of 
it. Start the fire in the windward end of the trench and no further 

J This lecture was presented November 18, 1918, and distributed January 20, 1919. 

100 



MYIASIS— ITS PREVENTION AND TREATMENT 201 

attention is necessary for several hours, when the extremities may be piled 
in the center to complete burning. The placing of wood on top of the 
carcass and addition of wood after the fire has started are unnecessary. 
About one-quarter of a cord of wood is adequate, and where wood is 
scarce, burning may be accomplished by using crude oil. Of course a 
few sticks of wood beneath the carcass will help hold the heat but 
this is not necessary. Ten to twenty-five gallons of crude petroleum are 
sufficient. The odor from carcass burning is not very objectionable, 
especially if the animal is destroyed soon after death. 

In cities it is usually feasible to have all large carcasses promptly 




Plate XIV. — Trench prepared for burning carcass. (Bishopp.) 

removed and effectually destroyed by commercial rendering and fertilizer 
plants. These establishments should be subject to sanitary inspec- 
tion. 

Carcass Burial. — Burial is generally unsatisfactory, especially if 
bodies are well infested with maggots. We have found that at least 
twenty-four inches of finely packed earth are necessary to prevent their 
escape. The free use of quicklime on the body after it has been placed 
in the grave helps to destroy the maggots and reduce chances of disease 
spread. We have not yet undertaken experiments with the treatment of 
carcasses before burial with creosote oil, but judging by results obtained 
from treating those on the surface, this should be a good method of 
destroying larvae, reducing odor and killing disease organisms. 



202 SANITARY ENTOMOLOGY 

Treating with Chemicals. — Nearly all maggots of this class of flies 
are exceptionally resistant to the action of chemicals. We have found 
some to survive submergence in very destructive insecticides. Foreman 
and Graham-Smith, working in England, have found that creosote oil, 
which is one of the higher distillates from coal tar, is quite efficacious in 
the treatment of carcasses. Two things are accomplished — the majority 
of the larvse are actually hit by the spray and destroyed and decomposi- 
tion is practically stopped with corresponding reduction in odor. In 
recent experiments conducted at the Dallas Laboratory, we have found 
that several American makes of creosote oil are excellent for this purpose. 
Small carcasses thoroughly sprayed before infestation takes place will 
remain free from infestation, the flies being repelled by the substance 
and odor practically prevented. The carcass usually shrinks and as- 
sumes a mummified condition. Such creosote oils are manufactured by 
a number of concerns and usually sold at prices ranging from sixty- 
five cents to one dollar per gallon, according to the per cent of coal 
tar acids contained. Rather high percentage of these ingredients (at 
least 12 per cent) is best. 

Since direct sunlight is a powerful destructive agent in the semiarid 
and arid regions, if burning cannot be accomplished, the carcasses should 
be left in the most exposed place possible — not in a gully under shade as 
is usual. This will often result in about 85 per cent control. 

Disposition of Garbage. — The question of garbage disposal has been 
discussed briefly in other lectures (Chapters X, XI). Nearly all gar- 
bage is attractive to blow flies as well as other forms and the bone and 
meat scraps become infested. Where incineration is practicable it is 
most desirable. When fed to hogs the bones should be picked out and 
placed in a screened compartment or treated with borax or creosote 
<nl. 

Destruction of Flies. — In general the destruction of flies should be 
considered as secondary to the elimination of breeding places, but under 
certain conditions this method of attack has its place. 

Traps. — Various types of traps have been devised for destruction of 
flies but a careful comparison of many different forms in experiments car- 
ried out at the Dallas Laboratory shows that there is much difference 
in their efficiency and also that some minor changes in the construction 
of a trap may greatly improve the size of the catch. As a result of 
these experiments the fly trap described in Farmers' Bulletin No. 734 
is being recommended by the Bureau. This trap appears to be the best 
all round form for catching both house flies and blow flies. Of course 
the framework of the trap need not be made of hoops and barrel 
heads, as suggested in that bulletin, although those prove very satis- 
factory. The essential principles are to have the high cone, comparatively 



MYIASIS— ITS PREVENTION AND TREATMENT 203 

large opening at the top of the cone, screened area over the cone to admit 
light from above, screened sides so as not to cast shadow around the 
bait, and legs about one inch high. The tent traps are not as efficient 
as the cone traps and this inefficiency is especially marked in some 
makes of traps now being furnished the Army, which are built with a 
broad bottom on either side of the tent. This repels the flies to such an 
extent as to make the traps almost worthless. For blow flies this dark- 
ened area is not so objectionable as for the house fly. While not strictly 
a trap, the method of covering carcasses with burlap as recently sug- 
gested by Froggatt in Australia may be of value. Four stakes are driven 
into the ground around the carcass, and the tops of these are connected 
with a heavy wire. A canopy is then put over the stakes, brought to 
the ground and dirt piled on the edges. When the flies emerge they are 
imprisoned and soon die. If the canopy is not sufficiently large, there 
is danger of many escaping through the migratory habit of the larva?. 

Kind of Bait to Use. — This point has been discussed in a previous 
lecture. Animal matter is best for blow flies, and the packing-house ref- 
use known as "gut slime" is best of all. It is removed from intestines 
when sausage casings are made. Good baits and proper attention to kill- 
ing and rebaiting are essential to best results. 

Poisons. — It is possible to destroy large numbers of flies by means 
of poisoned baits. Arsenic solution (made by boiling arsenic in water) 
mixed with defibrinated blood, gut slime, or some other attractive bait 
will kill large numbers. This bait may be placed in covered containers 
to prevent dilution by rain. Cobalt may be substituted for arsenic. 
When carcasses can not be burned, Froggatt has advocated slashing 
them and spraying with arsenic solution. This poisons large numbers 
of flies and maggots and reduces the attractiveness of the carcass ; so 
much so, in fact, that birds and animals will not touch it. 

Avoidance of Attach on Man. — To prevent fly attack it is necessary 
to have wounds promptly and properly dressed. Man should avoid 
exposure by sleeping in the open during hot weather, especially if there 
is any trouble from catarrh or nose bleeding. Properly screened hos- 
pitals are of much importance and individual blow flies found within 
should be promptly killed. 

Avoidance of Attach to Animals. — In preventing screw-worm attack 
in cattle and other livestock, there are several important points to be 
considered. Breeding should be done so as to have calves come during 
fall, winter or early spring months. Branding and surgical operations 
should also be done out of screw-worm season. Care should be taken 
to avoid mechanical injury to stock. As the screw-worm flies are worst 
in brushy pastures, clearing out all underbrush will be found beneficial. 
Since many cases develop from infestation of ticks and mange, the de- 



204 SANITARY ENTOMOLOGY 

struction of ticks and mange mites on animals is important. Care 
should be taken to guard against extensive saddle or harness sores on 
army animals. 

Methods of preventing blowing of* wool on sheep hardly need to be 
discussed fully here. Shearing early in the spring, avoiding the soiling 
of wool, raising hornless breeds and the crutching, that is clipping the 
wool at the vent and behind the hind legs greatly reduces infestation. 

Treatment of Infestations in Man. — Nasal myiasis is the most dif- 
ficult to handle. The larvae should be removed mechanically as far as 
possible. A number of different treatments have been resorted to, the 
administration of chloroform into the nose being the most used. After 
all larvae have been taken away, it is usually necessary to exercise care to 
prevent breaking of blood vessels which are frequently greatly exposed 
by destruction of the surrounding flesh. In most wounds the larvae are 
quite easily removed. Of course the details of the care of the patient 
are to be determined by the physician in charge. 

Treatment of Woumds in Animals. — Chloroform is the most generally 
used of all reagents and is usually satisfactory. The chloroform is 
poured directly into the holes and the wounds closed up. This benumbs 
the larvae so that they can be taken out with a forceps. Carbon tetra- 
chloride is also satisfactory for this use and considerabty cheaper. 
After the larvae have been taken out antiseptic astringent dressing should 
be applied and pine tar or pine oil and vaseline applied to the outside 
to repel flies. Oil of camphor is an excellent fly repellent and aids in the 
healing process. Bleeding wounds should be dusted with tannic acid 
before applying the repellent. 

SUBDERMAL MIGRATORY SPECIES 

The reduction of the number of ox warbles in cattle is important 
from the standpoint of the raiser as well as to lessen the chances of 
infestation of man and horses. The most feasible method yet devised 
consists in the squeezing out of the larvae from the backs of the animals 
after they have formed the subcutaneous tumors. This should be done 
at intervals of about three weeks, all animals being gone over carefully. 
The period for beginning extraction varies according to latitude from 
October 15 to March 1. 

The question of controlling Dermatobia hommis in tropical America, 
and also its African analogue, Cordylobia anthropophaga, has not been 
sufficiently worked out to make satisfactory recommendations. No doubt 
where livestock are under control, systematic extraction will reduce the 
number of these, both in animals and man. When humans become in- 
fested it is usually advisable to allow the larva to become stationary and 



MYIASIS— ITS PREVENTION AND TREATMENT 205 

then remove it through the hole in the skin. It may be necessary to en- 
large the hole to get it out more easily. In the case of the American 
forms the bite from various bloodsucking Diptera should be prevented as 
far as possible. Having the body well protected with clothing will also 
probably reduce injury from both of these species. On account of the 
probability that some of the African parasites of this class deposit eggs 
on exposed clothing, especially if wet with perspiration, this should be 
guarded against. 

SPECIES CAUSING INTESTINAL AND UROGENITAL MYIASIS 

Control of Truly Parasitic Species. — In Animals. — There are 
three principal methods of attack against the bots of horses. The de- 




Fig. 40. — Nose protection for horse against attacks of the nose fly, Gastrophihts 

haemorrhoidalis. (Dove.) 



struction of eggs will accomplish much good in the case of Gastrophilus 
intestinalis and is applicable to some extent to G. nasalis, but apparently 
can not be practiced in G. haemorrhoidalis. Dove has found that the 
common practice of washing the legs of horses with kerosene oil has but 
little beneficial effect. The creosote derivatives containing about two 
per cent phenols destroyed the eggs readily. A miscible creosote com- 
pound reduced with water to this strength and applied with a rag or 
brush at the time the horses are groomed will destroy practically all 
eggs present. Such treatment repeated weekly should accomplish almost 
complete control. In this way horses and mules may be kept practically 
free from infestation. Of course the grooming itself will tend to hatch 



W6 SANITARY ENTOMOLOGY 

eggs and get rid of larvae. Clipping of the hair on the legs has also 
been recommended but is not entirely satisfactory. Dove has experi- 
mented with certain halter devices for the protection of horses in pas- 
tures and also with various types of guards to be used on horses in 
harness to prevent the attack of the nose fly (fig. 40). In the first case 
he used a halter, from which is suspended a box-like arrangement that 
covers the nose when the horse has its head up, but permits of grazing 
and drinking. A canvass extends back under the jaw to prevent deposi- 
tion of eggs by the throat bot, and of course the covering of the mouth 
prevents the ingestion of eggs of the common bot. The main difficulty 
has been the production of a durable device of this kind. The nose fly 
attack is best prevented by a rectangular piece of belting being suspended 
from the bit rings immediately below the lips, when horses are at work. 

The internal treatment of infested animals with carbon disulphide 
has been found to be very effective if properly done. Three three-dram 
doses at hourly intervals are given in capsules succeeding a period of 
starvation and followed by a purgative. 

Prevention of Attack in Man,- — The reduction of the number of bots 
by treatment of the lower animals will greatly reduce the chances of in- 
festation in man. Care should be taken not to ingest eggs or larva; 
when infested horses are being clipped or groomed. 

Prevention or Attack by Other Forms. — This group includes 
those species accidentally infesting man such as the Muscids Musca 
domestical and Muscina spp., Fannia, and Syrphus flies. 

Destruction of Breeding Places. — Since most of these forms are 
breeders in excrementitious matter and decaying vegetation, the proper 
care of manure of all kinds is important. This has been discussed in other 
lectures. Since some of the species, especially Fannia, breed in accumu- 
lations of decaying vegetation such as straw, roots, etc., these should 
receive attention, especially when close to camps. 

Destruction of Flies.— The use of traps is effective against most 
of the species concerned except the small Phorids and Syrphids which are 
not inclined to enter traps baited with usual baits. Poison baits and 
fly paper will also destroy some species other than the house fly. 

Food and Water. — The careful preparation of uncooked food such 
as cress, lettuce, etc., is important. No doubt many of the cases of infes- 
tation by Fannia and Eristalis have been due to the eating of improperly 
washed foods of this kind. Drinking promiscuously from streams and 
pools should not be permitted. During the Great War the provision of a 
good water supply for the men received first consideration. Of course 
this is important to prevent infestation with various disease organisms. 
Distillation, filtration and chlorination are the preferred methods of 



MYIASIS— ITS PREVENTION AND TREATMENT 207 

producing pure water. Where it is essential that water must be taken 
from streams care should be exercised not to drink near vegetation. 

Use of Screens. — Proper screening of houses will do much to protect 
foods after preparation from infestation, although some of the small 
forms can not be kept out in this way. A coarser mesh than 16 per inch 
should not be used. The use of screened toilets of course can not be too 
strongly emphasized. 

Cleanlkiess and Careful Habits. — Many infestations of the digestive 
system and genitalia could be avoided by not sleeping in unscreened places 
in an exposed condition. Prompt attention to infants is important. 

SPECIES INFESTING HEAD PASSAGES 

Infestations m Animals. — The parasitic forms are very difficult to 
control and no very satisfactory control measures have been devised. 
Nearly all of the recommendations made are of little value. Some of 
these consist of the use of repellents in the case of sheep to protect 
them from infestation by Oestrus ovis. Pine tar is most frequently used 
and this is applied by the sheep themselves. Holes in logs are used for 
salting and the sides are smeared with tar. The provision of plowed 
furrows where the sheep can protect their noses probably gives some 
relief. For very valuable animals screened pens are no doubt warranted, 
the animals being placed in these during the portion of the day when 
the flies are most active. There seems to be considerable difference in 
effect of attacks on breeds. Attempts to remove the larvae from the nose 
by causing sneezing or with fumigants are more likely to drive the larvae 
deeply into the head than to remove them. Trephining the skull and 
removing the larvae in that way may give some relief but is usually not 
advisable as other infestations are likely to follow and all the grubs 
can not be reached. Destruction of adults has been advocated and is 
especially applicable to plains areas, as in such places flies are inclined 
to congregate on any objects which extend well above the ground. The 
flies assemble on such objects and remain there except during the warmer 
part of the day and many can be killed. 

Many of the control measures suggested for the control of the sheep 
bot can be used against the horse infesting species, Rhinoestrus pur- 
pur eus. It might also be possible to utilize muzzles similar to those advo- 
cated for the horse bots to protect against infestations from this species. 

Infestations in Man. — Infestations of man are so infrequent that pre- 
ventive measures need receive little attention. Where such infestations 
either by the sheep head maggot or horse head maggot are common 
the use of nets on the hats similar to those used by apiarists would 
give protection. Medical attention should be given promptly for re- 
moval of larva% especially if in the eye. 



208 SANITARY ENTOMOLOGY 

BLOODSUCKING SPECIES 

In Birds. — Since these dipterous parasites are often highly injurious 
to birds, and especially to certain beneficial varieties, control measures 
should be considered although nothing has been done along this line. In 
the Southwest it is stated that the mortality among birds is very high 
owing to these parasites. 

Possibly trapping of the adults in connection with the control of 
other destructive species would be feasible. 

In Man. — The Congo floor maggot is the only species in this group 
requiring special attention. The use of beds instead of sleeping mats 
laid directly on the floor will give immediate relief. Where beds are not 
at hand hammocks may be used. The avoidance of sleeping in huts 
is advisable. Thorough cleansing and disinfection of the floor should 
destroy many maggots and the elimination of cracks in the dirt will 
check their breeding. Where sleeping mats are used by the natives 
they should be sunned and aired frequently. It is said that the maggots 
are carried from one hut to another in these mats, so that moving the 
place of abode does not eliminate the trouble. 



CHAPTER XIV 

Diseases Transmitted by Bloodsucking Flies 1 
W. Dwight Pierce 

As stated before it was necessary to discuss the transmission of 
diseases by flies in three lectures, non-bloodsucking flies, mosquitoes and 
other bloodsucking flies. This is therefore the second lecture on fly- 
borne diseases, and embraces quite a different category of diseases. For 
convenience of reference and stud} 7 it will be likewise handled from the 
standpoint of the organism transmitted. The most important volume on 
the subject of this lecture is by Hindle. 

PLANT ORGANISMS CARRIED BY BLOODSUCKING FLIES 

Thallophyta: Fungi: Schizomycetes: Bacteriaceae 

Bacterium tularense McCoy and Chapin, the causative organism of a 
RODENT PLAGUE, is probably normally carried by fleas, but Wayson 
records some interesting experiments with the stable fly, Stomoxys cal- 
citrans Linnaeus. He found that a fly after biting an acutely diseased 
guinea pig eight times, if applied to a healthy animal within an hour, will 
effectively transmit the disease to the healthy animal and cause its death 
in five to nine days. Washings of the flies in normal salt solution, and 
also washings of the flies slightly crushed, when injected subcutaneously 
will produce similar results. The transmission by bites occurs only from 
those animals having an advanced stage of the bacteremia, as indicated 
by their death within 24 to 48 hours after the fly feeding. The flies have 
not been proven infective as long as 24 hours. This same organism has 
been isolated from cases of DEER FLY FEVER or PAHVANT VAL- 
LEY PLAGUE in Utah by Francis (1919). The disease is local and one 
case in 1919 was fatal. The fever, lasting from 3 to 6 weeks, is said to 
be initiated by the bite of deer flies (Chrysops). 

Bacterium antliracis Davaine, the causative organism of ANTHRAX 
or charbon, can be carried by bloodsucking flies. Nuttall (1899) cites 
many early references to the role of bloodsucking flies in the transmis- 

1 This lecture was presented October 7, 1918, and distributed October 19. It has 
been somewhat modified for the present edition. 

209 



210 SANITARY ENTOMOLOGY 

sion of anthrax, the earliest being by Montfils in 1776. Hintermayer 
(1846) studied an epidemic which raged among the deer in the Park of 
Duttstein. The horse flies, Tabanus bovinus Loew, Haemotopota plu- 
vialis (Linnaeus), and Chrysops coecutiens (Linnaeus) assembled usually 
in thousands on the carcasses of the fallen animals and sucked the pro- 
fluvia which escaped from the mouth, nose, and vent. Leaving the bodies 
they immediately sought the healthy animals, thrust their proboscides 
soiled with the virus into the skin and in this way inoculated the poison 
of the disease. Mitzmain (1914) proved that Tabanus striatus Fabricius 
and the stable fly, Stomoxys calcitrans Linnaeus, can transmit the disease 
by their bites. Schuberg and Kuhn (1912) transferred anthrax infection 
from a cadaver to a living animal through the bite of Stomoxys cal- 
citrans. 

Morris (1918) working on anthrax in Louisiana proved that the 
horn fly Lyperosia irritans Linnaeus (Haematobia) when biting an in- 
fected guinea pig four hours or less before its death and up to fifteen 
minutes after death can transmit infection. One hundred and eighty- 
four experiments on different guinea pigs were made during these time 
limits and infection was conveyed in 34 per cent of the cases. Forty 
experiments outside of these time limits were unsuccessful. One out of 
two tests with the flies feeding on an infected sheep thirty minutes before 
death yielded infection in a guinea pig, and all tests of biting in the quar- 
ter hours before and after death of the sheep yielded infection in guinea 
pigs. 

He also tested a species of Tabanus and proved transmission in 40 
per cent of 70 cases in which the flies bit between four hours before death 
and five minutes after death. Virulent cultures of anthrax were obtained 
in nature by Morris from Tabanus atratus Fabricius caught feeding on 
a carcass. This species will feed on a carcass thirty minutes or more 
after death. 

He likewise determined the spores in the feces of the Lyperosia up to 
six hours after feeding, of the Tabanus one to twelve hours after 
feeding, and of mosquitoes 48 to 72 hours after feeding. 

The above cited evidence should be sufficient to emphasize the absolute 
necessity of isolating and protecting from bloodsucking insects, animals 
sick with anthrax. Valuable animals should likewise be kept in screened 
buildings during outbreaks of the disease. 

Thallophyta: Fungi: Schizomycetes: Coccaceae 

Staphylococcus pyogenes albus and aureus Rosenbach, the causative 
organisms of various types of SEPTICAEMIA, were obtained by Joly 
(1898) from a Tabanus on a heifer near a municipal vaccine station. 



DISEASES TRANSMITTED BY BLOODSUCKING FLIES 211 

Streptococcus sp., causative organism of SEPTICAEMIA, was re- 
corded from Stomoxys calcitrans Linnaeus bv Schuberg and Boing 
(1914). 

DISEASES OF UNKNOWN OR UNCERTAIN ORIGIN 

PAPPATACI FEVER, also known as Three-day and Phlebotomus 
fever, a disease of the Mediterranean regions, which has caused consid- 
erable disability to the troops, especially in Egypt and Greece, is trans- 
mitted by the bite of the sand fly, Phlebotomus papatasii Scopoli, and 
possibly other species in the genus. This disease is considered very closely 
related to dengue, if not identical, by Megaw (1919) and others. Its 
transmission has been clearly demonstrated by Doer, Franz and Taussig 
(1909). The blood is infective for only about 24 hours. During this 
period the flies become infected by feeding on the patient. After ingesting 
the virus, there is an incubation period of seven to ten days before the 
insects become infective, and beyond this after an indeterminate period 
they may again become non-infective. Following the bite of an infected 
fly, there is an incubation period in man of from 3% to 7 days, during 
which time the patient is non-infective. The virus is filterable. Lizards 
and reptiles are the wild reservoirs of the disease. 

VERRUGA PERUVIANA, or Carrion's disease, a Peruvian disease, 
thought to be caused by Bartonella bacilliformis Strong, Tyzzer, Brues, 
and Sellards is claimed by Townsend (1916) to be carried by Phlebotomus 
verrucarum Townsend, and he advances evidence to support his claim. 

EQUINE INFECTIOUS ANEMIA, or swamp fever of horses, a 
disease caused by a filterable virus in Japan, was thought to be carried 
by Chrysops japonicus Wiedemann, Chrysozona pluviatilis Linnaeus 
(Haemotopota tristis Bigot), Tab anus chrysurus Loew, T. trigonus 
Coquillett, T. trigeminus Coquillett, and Atylotus rufidens Bigot, ac- 
cording to the Horse Administration Bureau (1914) ; and in America 
was claimed by Scott (1915) to be carried by Stomoxys calcitrans 
Linnaeus. Howard (1917) conducted an experiment with Stomoxys cal- 
citrans which indicated the probability that this fly transmitted the 
disease. 

HOG CHOLERA, a disease caused by a filterable virus, has recently 
been transmitted by inoculating animals with infected Stomoxys calci- 
trans (Dorset, et al., 1919). 

GLANDERS is associated by Fuller (1913) with Stomoxys cal- 
citrans outbreaks. 

POLIOMYELITIS, or infantile paralysis, a disease of unknown 
origin, has been suspected by various authors of being transmitted by 
biting insects, especially Stomoxys calcitrans and Tabanids. Rosenau 



212 SANITARY ENTOMOLOGY 

and Brues (1912) conducted experiments with this fly and reported suc- 
cessful inoculations of six monkeys by bites of the flies. Anderson and 
Frost (1912) repeated these experiments and as a result three monkeys 
exposed daily to the bites of several hundred Stomoxys, which at the 
same time were allowed daily to bite two intracerebrally inoculated mon- 
keys, developed quite typical symptoms of poliomyelitis eight, seven, and 
nine days, respectively, from the date of their first exposure. Autopsy 
of all proved the presence of typical poliomyelitis lesions. On the other 
hand these same authors in further experiments (1913) and Sawyer and 
Herms (1913) record negative results with this fly. Fuller (1913) re- 
ports that it has been shown that epidemics of infantile paralysis usually 
occur with an abundance of the stable fly. 

PELLAGRA, a disease of unknown origin, introduced from Europe 
to America, was for a long time thought to be caused by eating spoiled 
corn. At present sentiment seems to favor considering that it is caused 
by lack of vitamines. However, it is important that we discuss in this 
lecture rather briefly the theories propounded regarding bloodsucking 
flies as possible transmitters of the disease. 

Sambon (1910) brought forward the theory that the disease is car- 
ried by the buffalo gnats Simulium spp. Jennings and King (1913b) 
and Jennings (1914) are inclined to believe that the incidence of this 
genus and of pellagra affords sufficient evidence to exclude Simulium from 
the consideration. On the other hand Jennings and King in their three 
papers point out very strongly the possibility of Stomoxys calcitrans 
being concerned in the transmission of the disease. 

RICKETTSIA MELOPHAGI Noller, a body similar to those found 
in typhus, trench fever, etc., is found in the bodies of Melophagus ovinus, 
the sheep tick, but is not known to be associated with any disease. 



ANIMAL ORGANISMS TRANSMITTED BY BLOODSUCKING FLIES 

Protozoa 

Mastigophora: Binucleata: Haemoproteidae 

Haemoproteus columbae Celli and San Felice, the cause of PIGEON 
MALARIA or haemoproteasis of Columba livia, is transmitted by the 
pigeon flies Lynchia maura Bigot in Algeria and India, and L. brunea 
Olivier in Brazil. Mrs. Adie (1915) worked out the complete life cycle 
in the fly, and Acton and Knowles (1914) in the pigeon. Mrs. Adie 
succeeded in transmitting the disease to uninfected pigeons by the bites 
of Lynchia flies. The flies used were dissected and found to contain 



DISEASES TRANSMITTED BY BLOODSUCKING FLIES 213 

zygotes and sporozoites. Parasites were found in the blood of the 
pigeons 28 days after the flies were first put on them. 

In the pigeon the asexual cycle is passed. The sporozoites are inocu- 
lated by the bite of the fly. They enter the red blood corpuscles in the 
lung capillaries where they develop into trophozoites and schizonts and 
divide into merozoites, which may continue the asexual c} r cle by entering 
other corpuscles and becoming trophozoites. On the other hand they 
may remain in peripheral circulation and develop into the sexual forms, 
the macro- and microgametocytes. These forms may persist in the 
pigeon's blood over winter. They are ultimate^ taken up from the 



Host I (Pig con). 




HostII (Fly) 


/>Z f (A X-%. 

/V-- CIRCULATION. \.\: 


1 /(f\ C«t /in VV 

> £ /%/ i„, \ / Lowcn V^A 
*~ a d \ / Portion or \-<< 
— 'J 1 / Proboscis \ / „ „ 1* 
==1 / sexual MidGut ^ 


°5\ cVC API LLARIES\ / / \ 
W\ ^V \ / °/ \ 

. IN0CULAT10I 
Of PIGEON BY 
. BITE OF FLY 


In o ; cle -^ J* 
Salivary / 1 | N ^^^^_ /£ 

l Glands /J ^"7*/ 

A/ J WAL^X/ 


1 

CYCLE OF 




l 

cycle or 


Schizogony in 




Sporogony in 


Columba Livia (Pigeon). 




Lynchia Maura (Fly). 



LIFE CYCLE OF HAEMOPROTEUS COLUMBAE 



The Cause Of Pigeon Malaria, 
Fig. 41. (Pierce.) 



pigeon's blood by the fly and pass from its proboscis into the gut. They 
develop into gametes which conjugate to form zygotes in the lower por- 
tion of the mid-gut. These become ookinetes and develop into oocysts 
in the gut wall. The oocysts divide into a multitude of sporozoites which 
find their way through the body cavity into the salivary glands and are 
ready for inoculation. 

The life cycle is graphically shown in the chart (fig. 41) which 
should be compared with that of Plasmodium (fig. 47) in the lecture 
on mosquito-borne diseases. 

Haemoproteus mansoni Sambon, the cause of HAEMOPROTEASIS 
OF THE RED GROUSE, is transmitted by the grouse fly, Ornitlwmyia 
lagopodis Sharp in which Sambon found ookinetes in the stomach. 



214 SANITARY ENTOMOLOGY 

Certain species of Haemoproteus are mentioned in another lecture 
as transmitted by mosquitoes (see Chapter XVII). 

Mastigophora: Binucleata: Leucocytozoidae 

Leucocytozoon lovati Sambon and Seligman, the cause of LEU- 
COCYTOZOASIS OF THE RED GROUSE, Lagopus scoticus, is sup- 
posed by Fantham to be likewise transmitted by the grouse fly, Orni- 
thomyia lagopodis Sharp, in which he found vermicules. 

Mastigophora: Binucleata: Trypanosomidae 

As has been mentioned before, Chalmers' new classification of Trypan- 
osome genera is used in this volume, although criticized by Mesnil. The 
value of this classification can be seen in the various lectures in that it 
groups together species with similar host relationships. The two genera 
involved definitely in biting fly transmission are Castellanella and Dut- 
tonella. In the former the final stage in the insect takes place in the 
salivary glands, and'in the latter, elsewhere in the anterior portions of the 
insects. Those species which can not be definitely assigned to a genus 
are left in Trypanosoma (sens. lat.). 

Castellanella annamense (Laveran), cause of an EQUINE TRY- 
PANOSOMIASIS in Annam, is believed to be carried by Tabanidae and 
Hippoboscidae according to Castellani and Chalmers. 

Castellanella brucei (Plimmer and Bradford) Chalmers, cause of 
NAGANA, an African disease affecting many wild and domestic animals, 
is transmitted normally by bites of the tsetse flies, Glossina morsitans 
Westwood, G. brevipalpis Newstead, G. pallidipes Austen, G. tachinoides 
Westwood, and G. fusca Walker, and may also be transmitted by the 
horse flies Atylotus nemoralis Meigen, and a Tabanus, and by the stable 
flies Stomoxys calcitrans Linnaeus, and S. glauca. The organism must 
undergo part of its development in the alimentary canal of the fly. When 
fully developed it is found in the proboscis and is then capable of being 
inoculated into animals by the bite of the fly. Trypanosoma sp., cause of 
AINO, an African disease of cattle probably identical with C. brucei, is 
suspected by Brumpt to be carried by Glossina longipenms Corti. 

Castellanella dimorphon (Laveran and Mesnil^ Chalmers, cause of an 
African ANIMAL TRYPANOSOMIASIS, is carried by the tsetse flies, 
Glossina, palpalis Robineau-Desvoidy, G. tachinoides Westwood, G. mor- 
sitans Westwood, and G. longipalpis Wiedemann, and possibly by 
Lyperosia. The trypanosomes upon being taken up by the fly become 
established in the hind intestine and gradually extend forward until they 
reach the proboscis, when they become fixed and assume the leptomonad 
or crithidial form. 



DISEASES TRANSMITTED BY BLOODSUCKING FLIES 215 

Castellanella equiperdum (Doflein) Chalmers, cause of DOURINE of 
horses, has been experimentally transmitted by interrupted feedings of 
the stable fly, Stomoxys calcitrans Linnaeus and Atylotus foment osus 
Macquart by Sergent and Sergent (1906). 

Castellanella evansi (Steel) Chalmers, cause of SURRA of cattle and 
horses, has been experimentally transmitted by bites of Stomoxys calci- 
trans Linnaeus, S. geniculatus Bigot and S. nigra Macquart. Either 
experimental evidence or strong suspicion points to transmission by the 
horse flies, Tabanus tropicus Linnaeus, T, striatus Fabricius, T. lineola 
Fabricius, T. atratus Fabricius, T. fumifer Walker, T. partitus Walker, 



fwm (man) 



Host HCTsetsi: Fly) 




LIFE CYCLE OF TRYPANOSOMA GAMBIENSE. 

The Cause Of Gambian Sleeping Sickness OfMan 

Host I Traoelaphus spekei (Antelope). 
HostI/H.Glossina palpalis (tsetse flv). 
Host!. Homo sapiens (Man). 

Fig. 42. (Pierce.) 



T. vagus Walker, T. minimus Van der Wulp, and other species of Tabanus 
and Haematopota. Certain writers have also suspected Lyperosia minuta 
Bezzi, Philaematomyia crassirostris Stein and Lyperosia exigua Meigen 
(Haematobia). The parasite has also been found in the stomach of 
Stomoxys geniculatus. 

Castellanella evansi mborii (Laveran), cause of MBORI, a camel 
trypanosomiasis of Africa, is believed to be carried by Tabanus taeniatus 
Macquart and T. biguttatus Wiedemann. 

Castellanella gambiense (Dutton) Chalmers (nigeriense Macfie), 
cause of GAMBIAN AND NIGERIAN SLEEPING SICKNESS of man, 
has wild animals for its reservoir, and is principally transmitted by Glos- 
sina palpalis Robineau-Desvoidy and its variety fuscipes. Experimental 



216 SANITARY ENTOMOLOGY 

evidence indicates that it can be carried by Glossina morsitans West- 
wood, G. fusca Walker, G. longipennis Corti, G. pallidipes Austen, G. 
brevipalpis Newstead, G. tachirioides Westwood, as well as Stomoxys 
calcitrans Linnaeus, and the mosquitoes mentioned in another lecture. 
After the trypanosomes are ingested in the blood of the fly, multiplication 
begins, usually in the midgut (fig. 42). After the tenth or twelfth day, 
many long, slender trypanosomes are found which gradually move for- 
ward into the proventriculus. Such long, slender forms represent the limit 
of development in the lumen of the main gut. The proventriculus type, 
developed about the eighth to the eighteenth or twentieth day, is not 
infective ; it may occur in the crop, but is not to be found permanently 
there. Between the tenth and fifteenth days multinucleate forms of 
trypanosomes are found, and may be styled multiple forms. Some of 
these latter may be degenerative. Long slender forms from the proven- 
triculus pass forward into the hypopharynx. They then pass back 
along the salivary ducts, about sixteen to thirty days after the fly's 
feed. In the salivary glands they become shorter and broader, attach 
themselves to the surrounding structures and assume the crithidial facies. 
They remain attached to the wall and multiply. These crithidial stages 
differentiate into the short, broad trypanosome forms, capable of swim- 
ming freely. These forms only are infective. 

After inoculation into the vertebrate these forms multiply by longi- 
tudinal division. Repeated division occurs until the blood swarms with 
parasites. They then disappear from the blood and become latent non- 
flagellate bodies in the intestinal organs. These latent bodies again 
become flagellate and enter the general circulation, and may be taken up 
by a bloodsucking fly. The above life cycle was worked out by Miss 
Robertson as well as other workers and briefed by Fantham, Stephens 
and Theobald. 

Castellanella pecaudi (Laveran), cause of BALERI, a fatal equine 
trypanosomiasis of Africa, is usually spread by Glossina longipalpis 
Wiedemann and G. morsitans Westwood, but G. tachmoides Westwood 
and exceptionally G. palpalis Robineau-Desvoidy may be infected. 
Stomoocys calcitrans Linnaeus and S. nigra Macquart are recorded as 
possible carriers. The incubation period in G. longipalpis is 23 days. 
The trypanosomes multiply in the fly intestine up to 48 hours after 
ingestion in a modified form, called by Roubaud the "intestinal try- 
panosome form." Under favorable conditions these multiply very rapidly 
and in seven to nine days invade the whole of the intestine as far as the 
pharynx. These flies are not infective until the parasites have invaded 
the proboscis and passed through the crithidial and leptomonad phases. 
These proboscis forms multiply and some reach the hypopharynx, where 



DISEASES TRANSMITTED BY BLOODSUCKING FLIES 217 

they assume the "salivary trypanosome form" and are then capable of 
infecting any susceptible animal (Hindle). 

Castellanella rhodesiense (Stephens and Fantham) Chalmers, cause 
of RHODESIAN SLEEPING SICKNESS of man, is carried by Glossina 
morsitans Westwood, G. palpalis Robineau-Desvoidy, and G. brevipalpis 
Newstead. The insect becomes infective after an incubation period of 
about, 14 days and is infective throughout the remainder of its life. The 
life cycle is not completely worked out, but it is known that the try- 
panosomes first become established in the intestines and later invade the 
salivary glands (Hindle). 

Castellanella soudanense (Laveran) Chalmers, cause of TAHAGA of 
dromedaries in Sudan, EL DEDAB of dromedaries in Algeria, and 
ZOUSFANA of horses in Sud Oranais, has been experimentally trans- 
mitted by Stomoxys calcitrans Linnaeus, S. nigra Macquart, Atylotus 
nemoralis Meigen, and A. tomentosus Macquart. 

Duttonella caprae (Kleine) Chalmers, cause of an African goat Try- 
panosomiasis, is transmitted by Glossina brevipalpis Newstead and G. 
morsitans Westwood. 

Duttonella cazalboui (Laveran) Chalmers, cause of SOUMA, an 
African animal trypanosomiasis, is principally carried by the tsetse flies 
Glossina palpalis Robineau-Desvoidy, G. longipalpis Wiedemann, G. mor- 
sitans Westwood, and G. tachinoides Westwood, but may also be trans- 
mitted by Stomoxys calcitrans Linnaeus, Tabanus biguttatus Wiede- 
mann, and T. taeniatus Macquart, and possibly Stomoxys nigra Mac- 
quart. Development of the organism is restricted to the proboscis of 
the tsetse fly, the flagellates never multiplying in any other part of 
the alimentary canal. They may change in the proboscis into lep- 
tomonad or crithidial forms, attach to the walls of the labrum and under- 
go rapid multiplication. Under the influence of the salivary secretion 
some of these fixed flagellates develop into small, actively motile try- 
panosomes closely resembling the blood forms. This becomes infective 
from six to ten or more days after ingestion of the parasites. 

Duttonella cazalboui pigritia (Van Saceghem), cause of ZAMBIAN 
SOUMA of cattle, is carried by Haematopota perturbans according to 
Van Saceghem who found the organism in the intestinal tract of flies 
taken on infected animals. 

Duttonella congolense (Broden) Chalmers, cause of GAMBIAN 
HORSE SICKNESS, is carried by Glossina morsitans and possibly by 
G. palpalis and species of Glossina, Tabanus and Stomoxys. The various 
forms of the parasite have been demonstrated in the alimentary canal 
of G. morsitans %3 days after ingestion. 

Duttonella nanum (Laveran) Chalmers, cause of a fatal BOVINE 
TRYPANOSOMIASIS of Africa, is carried by Glossina palpalis, and 



218 SANITARY ENTOMOLOGY 

possibly G. morsitans. The development in the gut of palpalis is similar 
to that described above for T. gambiense. Multiplication begins in the 
hind intestine and by the tenth day numerous parasites are found in the 
hind and middle intestine. The slender forms begin to be produced from 
the tenth to the fourteenth day onward, and the proventriculus is 
usually invaded about the twentieth day. About the 25th day they invade 
the proboscis, where they may be found attached to the labrum, often 
lying in clusters. They then pass through the crithidial phase, many of 
them being extremely long and slender. Subsequently trypanosome forms 
are produced which may be found free, sometimes in the hypopharynx and 
at other times in the labrum. The salivary glands never become infected. 
(Taken from Hindle who summarizes the work of Duke and others.) 

Duttonella pecorum (Bruce, Hamerton, Bateman and Mackie), cause 
of a WILD ANIMAL TRYPANOSOMIASIS, is carried by Glossma 
morsitans, G. tachinoides, G. palpalis, and G. brevipalpis, in the alimen- 
tary canal of which it undergoes its cyclical development. 

Duttonella simiae (Bruce, Harvey, Hamerton, Davey and Lady 
Bruce), cause of SIMIAN TRYPANOSOMIASIS, is carried by Glossina 
morsitans and G. brevipalpis. 

Duttonella uniforme (Bruce, Hamerton and Mackie), a fatal TRY- 
PANOSOMIASIS of cattle, with wild animal reservoirs, is naturally 
carried by Glossma palpalis, which becomes infective in from 27 to 37 
days. The infection of the fly is always limited to the proboscis. 

Duttonella vivax (Ziemann) Chalmers, cause of a bovine and ovine 
TRYPANOSOMIASIS, is carried by Glossina tachmoides, and probably 
by G. palpalis and G. morsitans. Stomoxys and Lyperosia are suspected 
carriers. The incubation period of the fly is from five to eight days. 

Trypanosoma franU Frosch, cause of a TRYPANOSOMIASIS OF 
WILD GAME in Europe, is believed to be transmitted by Hippoboscidae 
and Tabanidae. 

Trypanosoma gallinarum, cause of FOWL TRYPANOSOMIASIS 
of the domestic fowl, is carried by Glossina palpalis, according to Duke 
(1912). 

Trypanosoma grayi Novy, cause of CROCODILE TRYPANOSOMI- 
ASIS in Africa, is carried by Glossina palpalis and G. brevipalpis. 

Trypanosoma theileri Laveran, thought to cause GALL SICKNESS 
of cattle by some authors, was experimentally transmitted by Theiler in 
South Africa by bite of Hippobosca rufipes Von Olfers and H. maculata 
Leach. 

Trypanosoma tullochi Minchin is native to Glossina palpalis in 
Africa, and no vertebrate host is as yet known. 



DISEASES TRANSMITTED BY BLOODSUCKING FLIES 219 

Mastigophora: Binucleata: Leptomonidae 

Crithidia melophagia Flu is normally a parasite of the sheep tick 
fly, Melophagus ovinus Linnaeus, and has been experimentally transmitted 
to rats and mice. Flu (1908) describes in the fly an asexual and sexual 
reproduction. The latter is characterized by a process of reduction, 
followed by conjugation with the formation of an ookinete and the infec- 
tion of the eggs of the insect, which may cause a second generation of flies 
to carry the organism. 

Crithidia nycteribiae Chatton is found in the parasite fly, Cyclopodia 
sykesi Westwood. 

Crithidia pangoniae Rodhain, Vandenbranden, Bequaert and Pons 
occurs naturally in Tabanus hilaris Walker, T . striatus Fabricius, and a 
Tab anus sp. 

Crithidia tenuis Rodhain, Pons, Vandenbranden and Bequaert is 
native to Haematopota duttoni Newstead, and H. vandenbrandeni Rod- 
hain, Pons, Vandenbranden and Bequaert in Belgian Congo. 

Leishmania brasiliensis Vianna, cause of BOUBA or oral leishmaniasis 
of Brazil and Paraguay, is believed by Brumpt and Pedroso to be carried 
by bloodsucking flies, either Tabanidae or Culicidae. 

Leishmania tropica (Wright), cause of BISKRA SORE in Algeria, 
and BAGDAD SORE in Bagdad, is believed by Wenyon (1911) and 
Sergent and Sergent (1914) to be transmitted by Phlebotomus mmutus 
africanus Newstead. 

Leishmania uta Escomel, cause of UTA, a dermal lesion peculiar to 
the western face of the Andes in Peru, is believed by Townsend to be 
carried by Forcipomyia utae Knab and F. townsendi Knab. 

Leptomonas minuta (Leger) occurs naturally in the intestine and 
Malpighian tubules of Tabanus tergestinus Egg. 

Leptomonas phlebotomi (Mackie) occurs in nature in Phlebotomus 
minutus Rondani in India. 

Leptomonas simidiae (Georgewitch) occurs in nature in Simulium 
columbaczense Schonberg in Europe. 

Leptomonas subulata (Leger) attacks Haematopota italica Meigen 
in Southern France. 

Mastigophora: Spirochaetacea: Spirochaetidae 

Spiroschaudwmia glossinae (Novy and Knapp) occurs in the stomach 
of Glossina. 

Telospo ridia : Haemogrega rmida : Haemogrega rinidae 

Haemogregarina francae De Mello, a parasite of the dove, Columba 
livia, is suspected of being carried by Lynchia maura Bigot. 



220 SANITARY ENTOMOLOGY 

Haemogregarma sp. passes its sporogony in Glossina palpalis but 
its vertebrate host is unknown. 



Metazoa 
Nemathelminthes: Nematoda: Filariidae 

Filaria (Loa) loa (Guiyot), cause of a human filariasis, was found by 
Ringenbach and Guyomarc'h in the Congo to pass part of its life cycle in 
Chrysops centurionis Austen, and by Leiper in West Africa in Chrysops 
dimidiata Van der Wulp, and C. silacea Austen. Leiper obtained a slight 
degree of infection but development was unequal and slow in Haematopota 
cordigera Bigot and Hippo cent rum trimaculatum Newstead. He 
obtained only negative results with Stomoxys nigra Macquart, S. calci- 
trans Linnaeus, Glossina palpalis Robineau-Desvoidy, Tabanus par 
Walker, T. socialis Walker, T. fasciatus Fabricius, and T. secedens 
Walker. 

Thus it will be seen that many of the most dangerous diseases of 
animals and some of the most dreaded human diseases are carried by 
bloodsucking flies, and furthermore, that the transmission is principally 
biological, that is, the insect is a necessary intermediate host. In this 
case the parasite invariably passes its cycle of sporogony in the inver- 
tebrate and its cycle of schizogony in the vertebrate, if it passes through 
such a cycle. 

A number of organisms found only in the insects are recorded. It is 
quite possible that some of these will ultimately be linked up with 
pathological species. Any one studying disease transmission must know 
in advance what organisms he might encounter in the insects he is 
studying. 

BIBLIOGRAPHY 

Anderson, J. F., and Frost, W. H., 1912.— U. S. Treas. Dept., Public 
Health Report, vol. 27, No. 43, Reprint No. 99, 5 pp. 

Anderson, J. F., and Frost, W. H., 1913.— U. S. Treas. Dept., Public 
Health Report, vol. 28, p. 833. 

Brumpt, E., 1902. — Arch, de Parasit., vol. 5, p. 158. 

Castellani, A., and Chalmers, A. J., 1913. — Manual of Tropical Medi- 
cine, 2nd edit. 

Doer, Franz, and Taussig, 1909. — Das Pappatacifieber. Franz Deuticke, 
Leipzig and Wien. 

Dorset, M., McBryde, C. M., Nile, W. B., and Rietz, I. H., 1919.— Amer. 
Joum. Vet. Med., vol. 14, No. 2, pp. 55-60. 

Duke, H. L., 1912.— Proc. Roy. Soo., vol. B 85, No. B 580, pp. 378-384. 



DISEASES TRANSMITTED BY BLOODSUCKING FLIES 221 

Fantham, H. B., Stephens, J. W. W., and Theobald, F. V., 1916.— The 

Animal Parasites of Man. William Wood & Co. 
Fiu, P. C, 1908.— Arch. f. Protistenk, vol. 12, pp. 147-153. 
Francis, Edward, 1919. — U. S. Treas\ Dept., Public Health Reports, vol. 

34, No. 37, pp. 2061, 2062. 
Fuller, C, 1913. — Fly Plagues. An unusual outbreak of Stomoxys cal- 

citrans following floods. Union of South Africa, Dept. Agr., circ. 32, 

1913. 
Hindle, E., 1914. — Flies in Relation to Disease. Blood-Sucking Flies. 

Cambridge Univ. Press., 398 pp. 
Hintermayer, 1846. — Centralarchiv. f. d. gesamte Staatsarzneikunde, 

Band 3, pp. 437, 441. 
Horse Administration Bureau, 1914. — Tokyo. Reviewed in Bull. Inst. 

Pasteur, vol. 12, No. 14, p. 634. 
Howard, C. W., 1917.— Journ. Parasit., vol. 4, pp. 70-79. 
Jennings, A. H., 1914. — Journ. Parasit., vol. 1, pp. 10-21. 
Jennings, A. H., and King, W. V., 1913. — (1) Journ. Amer. Med. Assoc, 

vol. 65, pp. 271-274; (2) Amer. Journ. Med. Sci., vol. 146, pp. 

411-440. 
Joly, P. R., 1898. — Importance du role des insectes dans la transmission 

des maladies infectieuses et parasitaires. — Du formol comme insecti- 
cide. Bordeaux. Imprimerie du Midi. 90 pp. Thesis. 
Leiper, R. T., 1914. — Rept. Advis. Comm. Tropical Research Fund for 

1913, London, p. 86. 
Megaw, J. W. D., 1919.— Indian Med. Gaz., vol. 54, No. 7, pp. 241-247. 
Mitzmain, M. B., 1914. — U. S. Treas. Dept., Hygienic Laboratory, Bull. 

94, 53 pp. 
Morris, Harvey, 1918. — Blood-Sucking Insects as transmitters of 

Anthrax or Charbon. La. Agr. Exp. Sta., Bull. 163, 15 pp. 
Nuttall, G. H. F., 1899. — On the Role of Insects, Arachnids and Myria- 

pods as carriers in the spread of bacterial and parasitic diseases of 

man and animals. A critical and historical study. Johns Hopkins 

Hospital Reports, vol. 8, Nos. 1, 2, pp. 1, 152. 
Ringenbach, J., and Guyomarc'h, 1914. — Bull. Soc. Path. Exot., vol. 7, 

pp. 619-626. 
Rosenau, M. J., and Brues, C. T., 1912.— Mo. Bull. State Bd. Health 

Massachusetts, vol. 7, No. 9, pp. 314-317. 
Sambon, L. W., 1910.— Journ. Trop. Med. and Hyg., vol. 13, No. 19. 
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61, pp. 461-465. 
Schuberg, A., and Boing, W., 1914. — Arb. Kais. Gesundheitsamte, Band 

47, Heft. 3, pp. 491-512. 



222 



SANITARY ENTOMOLOGY 



Schuberg and Khan, 1912. — Arb. Kais. Gesundheitsamte, Band 40, Heft 

2, pp. 209-234. 
Scott, J. W., 1915.— Science, vol. 42, No. 1088, p. 659. 
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665-681. 
Sergent, Ed., and Sergent, Et., 1914. — Bull. Soc. Path. Exot., vol. 7, pp. 

577-579. 
Townsend, C. H. T., 1916.— Journ. Parasit., vol. 2, pp. 67-73. 
Townsend, C. H. T., 1916.— Bull. Ent. Res., vol. 6, pt. 4, pp. 409-411. 
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Wenyon, C. M., 1911.— Kala Azar Bull., vol. 1, pp. 36-58. 



CHAPTER XV 

Biological Notes on the Bloodsucking Flies 1 
W. Dwight Pierce 

Mr. Webb, in his lecture which follows (Chapter XVI), has given us 
a very comprehensive view of the life history and habits of the horse 
flies of the genus Tabanus. In another lecture we presented the data on 
transmission of diseases by the bloodsucking flies and by reference to 
this (see Chapter XIV) it will be seen that quite a number of genera be- 
longing to several families of flies are concerned in disease transmission. It 
will be the aim of this lecture to present some of the salient biological facts 
concerning these genera so as to prepare the sanitarian for controlling 
those species in his territory, which might cause disease. 

The insects we have especially to deal with in this lecture are the 
sand flies of the genus Phlebotomus, in the family Psychodidae ; the horse 
flies of the genera Tabanus, Atylotus, Haematopota, Chrysops, and 
Chrysozona, of the family Tabanidae ; the biting flies of the genera 
Stomox} T s, Lyperosia, Haematobia, and Glossina, of the family Muscidae ; 
and the parasitic flies of the genera Melophagus, Lynchia, Hippobosca, 
and Ornithomyia, of the family Hippoboscidae. 

There are of course many other genera of bloodsucking flies which 
may contain potential disease carriers. Interesting discussions of these 
flies are to be found in the books by Hindle, and Patton and Cragg. 

FAMILY CHIROXOMIDAE 

Midges 

The little midges of this family are often mistaken for mosquitoes, to 
which they are somewhat related. Their young are the well-known 
blood worms in streams and stagnant pools. Of the five subfamilies 
only one, the Ceratopogoninae, contains bloodsucking forms. The eggs 
of Chironomidae are small and ovoid, or long and pointed at their extremi- 
ties, and are laid either in a gelatinous string of mucus or separately. 
The larva consists of thirteen segments, with head directed downwards, 
and mandibles well developed. On the ventral surface of the eleventh 

1 This lecture was presented October 14, and issued October 22, 1918. 

223 



224 SANITARY ENTOMOLOGY 

segment and the extremity of the twelfth, there are delicate finger-like 
processes, usually four in number, which serve as tracheal gills. The 
pupa is free and either lives floating in water without any movement or 
rests on the bottom of the pool. It has a tuft of delicate white threads 
on the dorsum of the thorax, which serve as breathing tubes; or it may 
have a pair of respiratory trumpets. 

Tersesthes torrens Townsend, a mountain form in North America, is 
a voracious bloodsucker, attacking man and animals, usually on the head, 
ears, and eyes. Its life history is unknown. 

Mycterotypus bezzii and M. irritans of Southern Europe are vora- 
cious bloodsuckers, biting human beings, as well as animals, and causing 
inflammatory swellings. 

Ceratopogon is a large genus containing a number of bloodsucking 
gnats called "punkies," found in various parts of the world. Some of the 
Asiatic species attack bloodsucking mosquitoes and draw blood from 
them. It is therefore possible that these insects may play a role in disease 
transmission. They are very small, measuring less than 3 mm. in length. 
Only the females are bloodsuckers. They bury themselves often among 
the hairs of the host and are not recognized until they become replete 
with blood. They often cause great distress on account of their num- 
bers and the irritation produced by their bites. The different species 
choose different parts of the host for attack, as for example, some select 
the face, especially the margins of the ears and eyes, while others may 
attack the arms or legs. 

Forcipomyia utae Knab is thought by Townsend to cause the South 
American disease, uta. Forcipomyia is considered to be a subgenus of 
Ceratopogon. Larvae have been found in crab holes and below the algal 
crust on the sand along the seashore in South America. 

Culicoides is another large genus of midges very similar to Cera- 
topogon, and contains many bloodsuckers. Only the females bite. The 
larva? are found in water under various conditions. When searching for 
larvae where the adults are abundant, they may be found by gathering 
in a white tray some of the green vegetable matter found at the edges of 
streams. The flies can be bred by placing the pupae on moist filter paper 
in tubes closed with moist cotton. 

The genera Johannseniella and Haematomyidium also contain blood- 
sucking midges. 

FAMILY SIMULIIDAE 

Buffalo Gnats 

The buffalo gnats of the genus Simulium are sometimes also called 
sand flies and turkey flies. This is a large genus of voracious flies which 
often are so numerous as to cause great distress and even death to men 



BIOLOGICAL NOTES ON BLOODSUCKING FLIES 225 

and animals. Sambon considered Simulium as the carrier of pellagra, 
but his theory has not been substantiated. Jobbins-Pomeroy has given 
quite a full treatment of the life history of several species of this genus, 
and Malloch has presented a classification of our American forms. The 
larvae breed usually in swift-flowing water. 

The eggs are small, rather triangular or ovoid objects, and somewhat 
yellowish in color after a few days. They are laid in masses on grass 
blades, or leaves, or on stones and other forms of debris at the surface 
of the water or under the surface. The egg stage varies in each species 
according to the temperature, but in Jobbins-Pomeroy's studies of five 




Fig. 43. Larva of a buffalo gnat, Simulium. (Jobbins-Pomeroy.) 



species, the incubation period ranged from 7 to 13 days. A single female 
may lay from 500 to 1500 eggs according to published claims. 

The larvae are invariably aquatic, and are quite characteristically 
marked by the possession of two large appendages on the head in front 
of the antennae, which are provided with fans of long hairs. These fans 
serve to brush food particles into the mouth of the larva (fig. 43). 

The mesothorax is provided with a single retractile proleg armed at 
its apex by a circular row of short booklets or spines. This pseudopod 
with its sucker is used by the larva in attaching itself to objects. A simi- 
lar but larger sucker-like disk is situated on the caudal extremity of the 
larva?. Respiration takes place through rectal gills located dorsallv to 
the caudal sucker. These skills are retractile into the rectum, but are 



226 SANITARY ENTOMOLOGY 

usually extended in running water. They function both as blood gills 
and tracheal gills. The structure of these gills affords characters of 
value for the identification of the species. 

The larvae attach themselves by the caudal suckers and float in the 
stream, catching their food by means of the fan-like processes on the 
head. When disturbed, or if the stream diminishes, the larvae let them- 
selves float down the stream attached by a silken thread to a permanent 
object, by which they can regain their former position. When about to 
pupate the larva spins over itself a pocket-shaped pupal case. The 
pupae are provided with respiratory organs on each side of the thorax. 
These are composed of long chitinous tubes with a single main stalk and 
four or more divisions. Good specific characters for identification are 
found in the structure of these respiratory organs (plate XV). 

The development period of Simulium in South Carolina is about 7 
days for the egg, 17 days for the larvae, and 4 days for the pupae. The 
number of generations depends upon the species and the season and may 
range from one to six or more generations. 



FAMILY PSYCHODIDAE 

Pappataci Flies 

The owl midges are small moth-like flies. Only the genus Phlebotomus 
contains bloodsucking flies, which are often called sand flies. The) 
pappataci fly, Phlebotomus papatasii Scopoli, cause of pappataci fever; 
P. minutus Rondani, a possible carrier of Bagdad sore, and P. ver- 
rucarum Townsend, supposed carrier of verruga, are the only species 
definitely charged with carriage of disease. Only the females suck 
blood. They deposit their eggs in damp, dark places, in clusters or 
singly, to the number of from 30 to 80. The eggs are covered with a 
thin coating of a sticky substance which causes them to adhere to any 
surface. They are very elongate, dark brown, with longitudinal, black, 
wavy lines. The incubation period is from six to nine days. The larvae 
live in damp earth. They are very peculiar, having large, well marked 
heads with big jaws, which have four distinct teeth. The body is covered 
with toothed spines and the posterior end bears two pairs of very black 
caudal bristles, one pair of which are as long as the body. The larva 
feeds on semi-decaying vegetable matter. The pupa is remarkable for the 
large ridges and excrescences on its thorax. The larval skin usually 
remains adhering to the caudal extremity. 

These flies breed in crevices of stone walls and fissures between rocks 
in caves, in dirty, damp cellars, and on the damp walls of latrines and 
cesspools, and wherever there is damp ground in dark places. Lizards fre- 



BIOLOGICAL NOTES ON BLOODSUCKING FLIES 227 



iAM\u /A 

M\ 1 / 

\h 1 1 f//f/ I 

NVi r///i i 

1 1* %y # i f 11// 



,1 l\x i\t IL 







Plate XV. — Pupae of Simulium. Fig. 1. — Respiratory filaments of pupa of SimuUum 
vittatnm. Fig. 2. — Pupa of Simulium venustum, in pupal ease. Fig. 3. — Pupa of 
Simulium bracteatum.: A, side view of filaments. Fig. 4. — Pupa of Simiilium jen- 
ningsi. Fig. 5. — Pupa of Simulium pictipes, in pupal ease. All greatly enlarged. 
(After Jobbins-Pomeroy.) From U. S. Dept. Agr. Bull. 329, Plate V. 



228 SANITARY ENTOMOLOGY 

quently serve as blood hosts and are considered the reservoirs of the fevers 
carried, especially pappataci fever. 

FAMILY CULICIDAE 

The mosquitoes which in an orderly arrangement would be treated 
here have been considered in other lectures (Chapters XVII to XIX). 

The families so far discussed belong to the Nematocera; the next 
family belongs in the Brachycera. 

FAMILY TABANIDAE 

Horse Flies 

The family Tabanidae contains the horse flies, gad flies, deer flies, 
many genera and species of bloodsuckers. The males throughout the 
family are flower feeders or feed on vegetable juices, and so likewise are 
the females in many genera. The eggs of Tabanidae are commonly laid 
in large, shapely masses on the leaves and stems of plants growing in 
marshy ground, or overhanging water. In some species they are deposited 
on stones or rocks above the water of streams, and are very difficult to 
discover. 

Mr. Webb has discussed for us the habits of Tabanus (Chapter 
XVI). We have seen also that species of Tabanus can carry the animal 
diseases anthrax, nagana, souma, surra, and mbori. The genus Atylotus 
can carry nagana and dourine ; Haematopota, surra and equine infectious 
anemia ; Chrysops and Chrysozona are probable carriers of equine infec- 
tious anemia. Various other genera are bad bloodsuckers, especially 
Pangonia. 

Tabanid larvae grow very slowly, feeding at first on small crustaceans 
which are abundant in water and moist earth. The larger larvae of many 
species feed almost exclusively on earth worms, whose body juices they 
suck out. Although the larval stage may require months for development, 
the pupal stage will usually be short. 

FAMILY MUSCIDAE 

The flies of the family Muscidae are mostly not bloodsucking flies. 
Principal among these genera which have the mouth shaped for sucking 
blood are the genera Glossina, Stomoxys, Lyperosia, Philaematomyia and 
Haematobia. 

Bloodsucking Fly Larvce 

The genus Auchmeromyia of Africa is very peculiar in that both larvae 
and adults are bloodsuckers. The adult flies are sensitive to light and are 



BIOLOGICAL NOTES ON BLOODSUCKING FLIES 229 

usually found in the darkest parts of the native huts. The females have 
two periods of oviposition about one month apart, and may deposit a 
total of as many as 83 eggs. They oviposit on the ground in the huts, 
preferably where urine has been voided. The larvae are exclusively blood 
feeders. They are able to resist starvation for long periods. If fed regu- 
larly they may mature in about 15 days. They remain in hiding during 
the day and suck the blood of sleepers at night. Pupation occurs in 
the puparium or last larval skin. The fly is probably spread from village 
to village in the egg or larval stage in the dirty mats which the natives 
carry about with them. 

Travelers in Africa should always avoid sleeping in native huts 
or on the ground in the vicinity of corrals or native villages, because of 
these larvae and also many other venomous and disease-bearing pests. 

The African genus Choeromyia also has bloodsucking larvae, the 
attack of which is not to be confused with the myiasis caused by the 
larvae of related genera, because these larvae are free living and do not 
remain attached to the host. 



Biting Species of Musca 

The genus Musca apparently is a transitional genus as it contains 
both non-bloodsucking and bloodsucking flies. Musca pattoni Austen, 
M. gibsoni Patton and Cragg, M. convexifrons Thomson, M. nigrithorax 
Stein, M. bezzii Patton and Cragg and M. comma Fabricius, all of India 
except the last, which is European, are bloodsucking. But these flies 
are incapable of puncturing the skin of an animal. They feed on the 
' blood and serum exuding from the bites of other bloodsucking flies. 
These flies breed in cow dung. M . pattoni always deposits in dung where 
it is collected in heaps, while gibsoni and convexifrons deposit in isolated 
patches of cow dung. 

True Biting Flies 

The true biting Muscids belong to the subfamilies Stomoxydinae, 
Glossininae and Philaematomyinae. 

Philaematomyia is a genus closely resembling Musca in appearance. 
It contains three Asiatic species, of which the best known is P. insignis 
Austen, which only attacks cattle. It breeds in cow dung where it is 
collected in heaps. Both sexes feed on blood although they have also 
been seen feeding on cow dung. This habit would surely make it possible 
for the fly to mechanically carry infectious diseases from dung to blood. 
it breeds quite rapidly. 



230 



SANITARY ENTOMOLOGY 



Stable Flies 

Stomoxys is a genus found principally in Asia and Africa, although 
S. calcitrans Linnaeus, the well-known biting stable fly, is almost world- 
wide in its distribution (figs. 44-46, plate XVI). This species is capable 
of carrying rodent plague, anthrax, septicaemia, nagana, souma, dourine, 
surra, baleri, and Gambian sleeping sickness, and has been connected by 
Scott with the transmission of equine infectious anemia and seriously 
suspected as a possible carrier of poliomyelitis and pellagra. 

A very complete bulletin by Bishopp is available for free distribution, 
describing the life history and control of the stable fly, so that it is not 




Fig. 44 (left). — Eggs of the stable fly (Stomoxys calcitrans) attached to a straw. 

Greatly enlarged. (After Bishopp.) 
Fig. 45 (center). — The stable fly: Larva or maggot. Greatly enlarged. (After 

Bishopp.) 
Fig. 46 (right). — The stable fly: Adult female, side view, engorged with blood. Greatly 
enlarged. (After Bishopp.) From U. S. Dept. Agr., Farmers' Bull. 540, figs. 
1, % 5. 



necessary to give a full discussion in this lecture. It generally breeds in 
moist straw and hay. Stacked straw which has been wet and partly 
rotted and hence is no longer available for stock food is a very favorable 
place for the fly to breed. Such straw should be dried as soon as possible 
by scattering, and then either be burned or plowed under. The stable 
fly does not often develop in manure, but where it does it may be con- 
trolled by measures taken against the house fly. This species is very 
annoying to mules, horses, and cattle and often to man. Horses and mules 
often become frantic in their efforts to escape the flies. 

As much care should be taken to prevent the breeding of the stable 
fly as the house fly. They are carriers of entirely different series of 
diseases and both are dangerous. Especial care must be observed to 



BIOLOGICAL NOTES ON BLOODSUCKING FLIES 231 




Plate XVI. — The stable fly, Stomoxys calcitrans. Fig. 1 (upper). — Eggs in straw. 
Fig. 2 (lower right). — Pupae in straw. Fig. 3 (lower left). — Adults on leg of 
cow. (Bishopp.) 



232 



SANITARY ENTOMOLOGY 



prevent breeding in straw which falls out of the stalls and windows of 
the stables. Where the stables adjoin a road, considerable straw may 
fall out of the windows and remain outside the building in a place where 
the horses do not come, and no one may think of removing this straw 
with the daily removal of manure. Here is an excellent place for 
Stomoxys to breed. Wherever marine weeds and debris are washed 
ashore and form considerable masses, Stomoxys is likely to breed. In 
plate XVII is shown the proper method of stacking straw to prevent 
fly breeding. 




Plate XVII. — Straw stack showing proper method of building strawstack. (Bishopp.) 

Horn Flies 

Haematobia sanguisugens is an Indian bloodsucker, which attacks 
cattle and horses. The principal species of horn flies belong to the 
genus Lyperosia, 2 of which L. irritans Linnaeus (plate XVIII) and L. 
exigua Meijere are the two commonest bloodsuckers. The latter is 
oriental. The horn fly was treated very fully by Marlatt in a circular 
now out of print. This species is so called because of the habit of the 
adults of clustering on the base of a cow's horn. The flies also cluster 
on other parts of the animal and cause great annoyance. Even when not 
feeding the flies rest on the cattle. The eggs are laid singly on the surface 
of wet dung. The moment the dung is dropped a swarm of flies dart from 
the animal to the dung and remain there a few seconds, during which time 
2 Dr. J. M. Aldrich does not recognize Lyperosia, but places our American species in 
Haematobia. — W. D. Pierce. 



BIOLOGICAL NOTES ON BLOODSUCKING FLIES 233 





Plate XVIII. — The horn fly, Lyperosia irritans. Fig. 1 (upper). — Flies on cow. Fig. 
2 (lower). — Cow pasture showing droppings improperly left to breed flies. 
(Bishopp.) 



234 SANITARY ENTOMOLOGY 

many eggs are deposited. The flies immediately return to the cow. The 
larvae migrate from the dung when about to pupate and the puparia are 
usually found at some distance away or under the sides of the patch of 
dung. The horn fly in America requires about IT days from egg to 
adult. 

Protection of the animal from the horn fly by the use of repellents is 
suggested. In this connection Graybill's bulletin on repellents should 
be consulted. Dipping vats and the cattle dip of the Bureau of Animal 
Industry (see Chapter XXXI, p. 442), now used in the control of the 
Texas fever tick, aid materially in reducing horn fly numbers. 

Two practical methods are available for attacking the larvae and 
pupae. One is to throw lime on the dung, but the better method is to spread 
out the dung so as to favor its rapid drying or to allow a number of pigs 
to run with the cattle. In their efforts to obtain undigested food particles 
the pigs will effectively destroy the dung as breeding places for the fly. 



Tsetse Flies 

The tsetse flies of the genus Glossina are among the most dreaded in- 
sects of Africa. They are the carriers of three or more types of sleeping 
sickness, of aino, nagana, souma, horse sickness, baleri, and other 
trypanosomiases of many domestic and wild animals. There are quite 
a number of species, and probably all are important, but G. morsitans 
Westwood and G. palpalis Robineau-Desvoidy, are the best known. Excel- 
lent discussions of each of the important species and tables for differen- 
tiation are given in the textbooks of Hindle, and Patton and Cragg. 

The reproduction in this genus is very remarkable, resembling that 
of the Pupipara and is probably the result of their exclusively blood- 
sucking mode of life. The female lays a single larva at a time, which is 
retained and nourished in the oviduct until it is full grown. After the 
larva is born it at once burrows into the ground and pupates. The larva 
is generally of a yellowish white color and bears at its posterior extrem- 
ity a pair of large dark-colored protuberances between which is a depres- 
sion into which open the spiracles of the eighth segment. It pupates 
within the puparium or last larval skin. The puparium is broadly ovoid 
in shape and by its caudal appendages affords a means of distinguishing 
the species. 

The habitats of the various species should be rather thoroughly 
studied by any one expecting service in the African tropics. In general 
the flies are found in moist forest regions, especially along river courses, 
but the temperature, moisture, and shade requirements seem to vary 
for the different species. 



BIOLOGICAL NOTES ON BLOODSUCKING FLIES 235 



PUPIPARA 



The suborder Pupipara is composed of several families of the queerest 
flies in the order. The insects of the families Nycteribiidae, Streblidae 
arid Hippoboscidae are all ectoparasites on warm blood vertebrates. All 
of the Streblidae and Nycteribiidae of which the life history is known, 
are parasitic on bats and some of them are quite probably the carriers 
of bat diseases. In the family Hippoboscidae we find the genera Lynchia, 
Hippobosca and Ornithomyia, mentioned as carriers of disease, and also 
Melophagus to which belongs M. ovinus Linnaeus, the sheep tick. The 
flies of the genus Lynchia which carry pigeon malaria, live almost 
exclusively on pigeons. They deposit larva? in the pigeon houses ; these 
larvae become puparia in an hour. Hippobosca is composed principally 
of species parasitic on mammals, one of which is thought to carry the 
gall sickness of horses in South Africa. The females deposit larvae which 
are incapable of movement. They slowly darken until the puparium 
resembles a seed. Lipoptena cervi is parasitic on deer. Melophagus 
ovinus, which is wingless, lives on sheep, sometimes proving to be an 
important pest. This insect may be eradicated by giving two thorough 
dippings at 24-day intervals in lime-sulphur-arsenic solution or in stand- 
ard coal tar-creosote or cresol dips, or nicotin solution (Imes). 

Outside of the stable fly and sheep tick, control measures for biting 
flies are not well worked out. Of course the primary essentials are 
protection of the animals from the bites of the flies and prevention of 
breeding. 

REFERENCES 

Bishopp, F. C, 1913.— The Stable Fly. U. S. Dept. Agric, Farmers' Bull. 
540. Available for free distribution. 

Graybill, H. W., 1914. — Repellents for Protecting Animals from the 
Attacks of Flies. U. S. Dept. Agric, Bull. 131. 

Hindle, Edward, 1914. — Flies in Relation to Disease. Blood-Sucking 
Flies. Cambridge Univ. Press. 

Imes, Marion, 1917. — The Sheep Tick and Its Eradication by Dipping. 
U. S. Dept. Agric, Farmers' Bull. 798. Available for free dis- 
tribution. 

Jobbins-Pomeroy, A. W., 1916. — Notes on Five North American Buffalo 
Gnats of the Genus Simulium. U. S. Dept. Agric, bull. 329. 

Malloch, J. R., 1914. — American Black Flies or Buffalo Gnats. U. S. 
Dept. Agric, Bur. Entom., Tech. Bull. 26. 

Marlatt, C. L., 1910.— The Horn Fly. U. S. Dept. Agric, Bur. Entom., 
Circ. 115. 

Patton, W. S., and Cragg, F. W., 1913.— A Textbook of Medical Ento- 
mology. 



CHAPTER XVI 

Biology and Habits of Horse Flies 1 
J. L. Webb 



In various parts of the United States and in many foreign countries 
horses, cattle, and similar animals suffer severely from the bloodsucking 
habit of the so-called horse flies of the genus Tabanus (plate XIX). 




Plate XIX. — Tabanidae attacking cattle: Tabanvs phaenops on cow's jaw, and T. 
punctifer on top of shoulder. (Bishopp.) 

The life history and habits of different species may vary greatly. Yet 
there are certain conditions common to all species. In general, the 
flies of this genus arc to be found in or near swampy areas of the country. 

1 This lecture was read October 7, 1918. 

236 



BIOLOGY AND HABITS OF HORSE FLIES 237 

The larval stage of most species is passed in the ground, and a 
certain degree of moisture is necessary for proper growth and develop- 
ment. Most species require very wet, cr saturated soil, others are able 
to develop in moderately moist earth. 



EGGS AXD EGG LAYING 

The eggs are deposited by the female fly in clumps of several hundred 
each, on vegetation, rocks, or other objects overhanging suitable places 
for development of the larvae. When the eggs hatch, the young larvae 
drop to the soil or water beneath and disappear from sight. Here they 
remain for several months, sometimes for one or two years, when, after 
passing through a short pupal period, they emerge as adult flies. 

In some cases the »egg mass as well as the place of oviposition is 
characteristic of the species, and renders identification easy, once the 
observer sees one of which he knows the identity. 

In the Sierra Nevada Mountains of Eastern California where I have? 
been studying tabanids for the past two years, the egg masses of the two 
most important species are very easily distinguished. The egg mass of 
Tabanus punctifer Osten Sacken is oblong, somewhat pyramidal in shape, 
and about the size of the end of a man's little finger (plate XX, fig. 1). 
It is usually deposited upon a bullrush or coarse grass stem, and from 
one to three feet above the surface of the soil or water. When deposited, 
as is the case with all horse fly eggs, the mass is milk white. In a day or 
so, however, the color darkens to a mottled gray and white. Eggs of this 
species are found most abundantly along lake shores. The egg mass of 
Tabanus phaenops Osten Sacken is to be found on grass blades, three 
or four inches above the soil in swampy places in meadows. This mass is 
considerably smaller than that of Tabanus punctifer, is elongate, and 
usually contains but two layers of eggs, while the other species usually 
has about five layers. The egg mass of T. phaenops is black a day or 
two after oviposition. This mass is inconspicuous and extremely hard to 
locate in nature. 

In the Egyptian Sudan, Harold King found the eggs of Tabanus 
Jcingi Austen deposited in rounded masses on rocks rising from the edge 
of a stream, generally overhanging the water, and from 6 inches to lo 
inches above the water level. He also found the masses of Tabanus 
ditaeniatus Macquart on grass growing in rain pools. The shape of the 
egg mass of this species was variable, — some being long and narrow, 
others short and broad. The same worker secured oppositions of 
Tabanus par Walker in a cage, on the under sides of leaves of a water 
weed growing in a vessel of water. He also secured the egg masses of 
Tabanus taeniola Palisot de Beauvois, the tabanid most frequently 



SANITARY ENTOMOLOGY 




Plate XX. — Tabanus punctifer. Fig. 1 (upper left). — Egg masses on grass. Fig. 
2 (upper center). — Larva, dorsal view. Fig. 3 (upper right). — Larva, lateral 
view. Fig. 4> (lower left). — Pupa, lateral view. Fig. 5 (lower right). — Pupa, 
ventral view. (Webb, photos by Dovener.) 



BIOLOGY AND HABITS OF HORSE FLIES 239 

accused of causing the death of camels, from grasses and weeds over- 
hanging rain pools. These masses were placed on the upper sides of 
the plants as they hung over the water. 

In Ohio, Hine records finding the egg masses of Tabanus stygius Say 
principally on the leaves of Sagittaria standing in shallow water, the 
female fly habitually placing the eggs just above the point where the 
petiole meets the expanded part of the leaf. 

Mitzmain, working in the Philippines, used a large cage to secure 
ovipositions of Tabanus striatus Fabricius. He found that egg laying 
invariably took place in the early afternoon, never later than % o'clock. 
Under cage conditions egg masses were deposited on projecting splinters 
of wood, suspended fibers of jute sacking, fine brass wire, a single animal 
hair, coarse iron wire, leaves of trees, and the woodwork on sides and 
ceiling of the cage, invariably upon the shaded portions, — as the under- 
sides of beams and partitions. The egg mass in some cases entirely 
surrounded the object on which it was deposited. The cage contained a 
tank of water with growing water plants. Apparently Mitzmain did 
not find eggs in the open. 

In Southern Nigeria, Neave found the eggs of Tabanus cor ax Loew 
in the bush on reeds or grasses overhanging mud. 

Near Alturas, California, during the past two seasons, I have found 
the egg masses of an unidentified Tabanus, to be very abundant on the 
undersides of leaves overhanging a small creek. They were found on the 
leaves of willow, alder, and rose bush; also occasionally on the leaves 
of Populus and on coarse grass blades. 

I have never been fortunate enough to observe the process of egg lay- 
ing, although on one occasion I came upon a female of Tabanus punctifer 
which had just finished ovipositing, and was still in position, head down- 
wards on a stem of coarse grass. She was occupied at the time in brush- 
ing the end of the abdomen over the pure white egg mass, apparently 
covering it with a kind of transparent cement. She was not disturbed 
by my close approach. In fact, I broke off the stem on which she rested 
and observed the brushing process at close range for some little time 
before she took flight. 

Neave mentions the fact that the eggs of Tabanus corax in Southern 
Nigeria are covered with an almost impervious cement. On one occasion 
an egg mass of this species, after being kept for two days in 70 per 
cent alcohol, produced a few larvae after being taken out of the alcohol. 
However, not all species of Tabanus cover the eggs with cement. The 
eggs of Tabanus phaenops in the Sierra Nevada Mountains are not so 
covered, and fall from their place of attachment soon after hatching. 
The number of eggs contained in the mass varies considerably. The 
easiest way of ascertaining the number in any given mass is by counting 



240 SANITARY ENTOMOLOGY 

the larvae that issue therefrom. During the past summer the larvae 
emerging from ten masses of Tabanus phaenops eggs were counted. The 
number per mass ranged from 156 to 385, giving an average of 281 + per 
mass. Larvae from fifteen masses of Tabanus punctifer eggs were counted. 
The range was found to be from 159 to 701 larvae, — an average of 366 -f- 
per mass. However, this method of arriving at the number of eggs per 
mass was very inaccurate in the case of Tabanus punctifer, as practi- 
cally all these egg masses were, to a greater or less extent, parasitized, and 
in several of the masses a large per cent of the eggs failed to hatch. 

Larvae from a series of five unidentified Tabanus egg masses collected 
near Alturas, California, were also counted. Here the range was from 
326 to 890, — an average of 509 + per mass, with no parasitism. 

Mitzmain records that the number of eggs per mass of Tabanus 
striatus in the Philippines varies from 270 to 425. He observed the 
oviposition under cage conditions and found that the eggs were deposited 
at the exact rate of 10 per minute. 

References in literature to the incubation period are extremely scarce. 
King gives the period for Tabanus kmgi as about 5 days, and for Tabanus 
par as 5 to 6 days. These species occur in the Egyptian Sudan. Neave 
gives the incubation period of Tabanus corax in Southern Nyasaland as 
about 5 days. Mitzmain determined the period for Tabanus striatus in 
the Philippines to be from 3 to 5 days. 

In my own experience in the Sierra Nevada Mountains, I have found 
that the eggs of Tabanus phaenops under laboratory conditions hatch in 
from 6 to 7 days, while those of Tabanus punctifer require 14 days. How- 
ever, in one case, a mass of T. punctifer eggs, after being kept a few days 
in the laboratory, was placed outdoors in the sun, with the result that 
the incubation period was shortened to 11 days. No doubt if the mass 
had been kept in the open from the time of oviposition a still shorter 
incubation period would have been recorded. The eggs of the unidentified 
species collected near Alturas, California, hatched in from 7 to 8 days 
under laboratory conditions. 

Usually most of the eggs in a mass hatch at about the same time, but 
in the case of Tabanus phaenops I have found straggling larvae emerging 
several hours after the majority of the larvae were in the water at the 
bottom of the incubation vial. 

In arranging for the incubation of Tabanus eggs I am accustomed to 
use a large glass vial with water in the bottom. The egg mass is then 
suspended in the vial over the water, usually by placing the stem or 
leaf, to which the mass is attached, against the side of the vial, and press- 



BIOLOGY AND HABITS OF HORSE FLIES 241 

ing a cotton stopper into the mouth of the vial tight enough to hold the 
egg mass in position. When the larvas emerge they fall into the water 
where they will remain alive for several days if undisturbed. The young 
larvas of Tabanus phaenops and those of the unidentified species from 
Alturas sink to the bottom of the water and remain there alive and in 
good condition, without rising to the surface for air. On the other hand, 
newly emerged larvas of Tabanus punctifer (plate XX, fig. 2) remain at 
the surface of the water constantly. In all these three species, the first 
molt occurs within a very few hours after hatching, and the cast skins 
are to be found floating in the water. 

Mitzmain is the only author I find mentioning the molting of Tabanus 
larvas. He noted 3 molts in the case of the larvae of Tabanus striatus in 
the Philippines. The first molt begins with larvae 7 days old, the majority 
molting before the 10th day. The second molt usually occurs after an 
interval of at least 4 days, and in some larvas as much as 8 days, that is, 
when 15 to 18 days old. The third molt, which discloses the pupa, is 
very variable as to the time of its occurrence, some individuals not pupa- 
ting until 3 months after the larvas emerge from the eggs, the majority, 
however, pupating in a much shorter time. In fact, Mitzmain reared flies 
from deposition of egg to adult in 52 days. 

As was stated in the beginning, the eggs are deposited above situa- 
tions suitable for the development of the larvas, so that the young larvae 
when they drop from the egg mass immediately find themselves at home. 
If it is a species which lives in mud under water, the eggs will be found 
overhanging water, and upon dropping from the eggs the 3'oung larvae 
will simply sink through the water to the mud beneath. If it is a species 
which prefers mud not submerged, the eggs will be found in the right 
position and the larvae upon dropping to the mud, immediately burrow 
into it. 

The food of Tabanid larvae consists of small crustaceans and other 
minute forms of animal life of a soft texture. As the larvas increase in 
size they may take coarser food. In breeding jars, I have seldom used 
any other food than earth worms cut into sections, and such small forms 
of life as may be gathered up with the mud placed in the jar. The larvas 
are cannibalistic and eat each other readily. Mitzmain states that the 
larvae of Tabanus striatus seem to prefer their own kind even when other 
food is available. For this reason it is well in attempting to rear larvae 
of this genus, to place but one larva in each rearing jar. I have, however, 
in some cases successfully reared more than one individual in the same jar. 

Sometimes it is much easier to locate the larvae of a given species than 
the eggs. In most cases in my own experience, I have found the larvae 
first. In the mountain valleys of Eastern California where considerable 
areas of pasture land are irrigated, the larvae of Tabanus phaenops are to 



242 SANITARY ENTOMOLOGY 

be found in low places where the ground is continuously wet. They are 
usually quite near the surface, and can be located by scratching in the mud 
and grass humus with the fingers. Where there is an accumulation of old 
dead grass matted down in water, larvae are frequently found in this 
grass. While this species prefers quite wet conditions, it is capable of 
withstanding considerable drought. In making a test of drought resist- 
ance I allowed one or two breeding jars containing larva? of this species 
to dry out completely. One larva survived these conditions and produced 
a perfect adult. The exact length of the larval stage of this species 
has not yet been determined. 

I have found the larvae of Tabanus punctifer to be quite numerous 
along the shore of a lake in the Sierra Nevada Mountains. There was 
considerable debris, — weeds, grass, and bulrushes washed up on the 
shore. It was in this mass of partially decomposed vegetation kept 
saturated by the waves of the lake, that the larvae seemed to flourish. 

Another Tabanus larva of an unidentified species was found in the 
same general locality in the moist earth along the sides of small rivulets 
high up on the lower mountain slopes. 

Prof. Hine records finding the larvae of Tabanus vivax Osten Sacken 
in Ohio in the mud of a stream bed under riffles. 

Likewise, King found larvae of Tabanus kingi in the Egyptian Sudan, 
under stones in a shallow stream where the water rippled over and around 
the stones. The larvae were usually found under rocks not covered by 
water. These larvae possessed pseudopodia specially fitted for clinging to 
the stones and crawling up to the surface of the water to breathe. 

The same writer found the larvae of Tabanus ditaeniatus living in mud 
at the bottom of a more sluggish stream, and coming to the surface of 
the water periodically to breathe. 

King also mentions rearing adults of Tabanus par from eggs obtained 
in a cage. The larvae were kept in jars of mud, and this mud was 
allowed to dry up several times, and for a period of 57 days no growth 
was made, yet when normal conditions were restored, the larvae began to 
grow and completed development. This is somewhat in line with my own 
experience with Tabanus phaenops, already mentioned. 

In the Philippines, Mitzmain found larvae and pupae of Tabanus 
striatus in large numbers in sand at many points on the shore of Laguna 
de Bay. 

Neave records finding Tabanus larvae in Northern Rhodesia in July 
and August in the sand and mud of river banks. They often occurred, 
especially if the mud was inclined to be dry, at a depth of as much as 
6 or 8 inches. 

According to Hine some species of Tabanus larvae live in water for a 
time and crawl out into dry ground, consequently one often finds Tabanid 



BIOLOGY AND HABITS OF HORSE FLIES 243 

larvae by digging in dry ground along the borders of ponds. He also 
states that the larva? of Tabanus atratus Fabricius are sometimes found in 
rotten logs. It is probable that Hine uses the term "dry ground" in a 
comparative sense, and that both the dry ground referred to and the 
rotten logs contained some degree of moisture. 

The length of the larval period varies greatly in different species, and 
even among different individuals of the same species. The shortest periods 
for this stage are found, as might be expected, in the tropics. Thus, 
Mitzmain records a minimum larval period of 9 days for Tabanus striatus 
in the Philippines. The maximum period is given for this species as 3 
months. Neave gives the larval period for Nyasaland Tabanids as 6 
months or more. 

In Ohio, Hine found in rearing Tabanus lasiophthalmus Macquart 
under laboratory conditions that in one instance the larval period was 
from June 30 to March 10, approximately 8% months. In the case of 
the species which I have been studying in the Sierra Nevada Mountains, 
the larval periods have not yet been determined, but all signs point to 
periods extending over two winters. As a matter of fact, data on the 
larval periods of species of Tabanus are verv meager. 



PUP^ 

When the time for pupation arrives, the larva usually seeks drier 
quarters, though some moisture is usually necessary to maintain life 
during this period. Larva 3 living in the mud of stream beds usually work 
their way to the drier soil of the stream banks in preparation for pupa- 
tion. Pupae of most species are much more difficult to locate in nature than 
larvaa. The length of the pupal period is usually comparatively short. 
Mitzmain gives the period for Tabanus striatus in the Philippines as from 
3 to 7 days, while King records that of Tabanus par in the Anglo- 
Egyptian Sudan as 6 to 8 days. Neave states that this period in Nyasa- 
land Tabanids varies from 10 to 16 or 18 days. In rearing Tabanus 
lasiophthalmus in Ohio, Hine found the pupal period to be 15 days. 

My records show that under laboratory conditions in the Sierra 
Nevada Mountains this period in Tabanus phaenops is from 14 to 22 
days, while that of Tabanus punctifer (plate XX, fig. 3) is 27 to 28 days. 

LIFE CYCLE 

The shortest life cycle from egg deposition to emergence of adult, 
which I find recorded, is 48 days, in the case of Tabanus ditaeniatus in 
the Anglo-Egyptian Sudan. King gives the life cycle as 48 to 131 days. 



244 SANITARY ENTOMOLOGY 

Mitzmain found the minimum life cycle of Tabanus striatus in the 
Philippines to be 52 days. 

The life cycle of Tabanus lasiophthalmus was found by Hine in one 
instance to be about 9 months. He states that the cycle of Tabanus 
stygius probably requires two years. 

As has already been indicated in discussing larval periods, it is 
probable that the species of Tabanus in the Sierra Nevada Mountains 
require two seasons for their life cycles. 

HABITS OF ADULTS 

Only female adult horse flies attack stock (plate XIX). The males 
are never found taking any interest whatever in warm-blooded animals. 
Their food consists of the nectar of flowers and other sweet substances. 
Females also feed readily on sweet substances. I have quite often cap- 
tured a few in a fly trap baited with banana. It appears that the primary 
object of the blood meal is to enable the female to develop eggs, although 
this diet may also be taken for nourishment. 

The males are usually to be found in the grass, or the foliage of trees, 
or on the trunks of trees, and when the females are not sucking blood 
they will usually be found in the same situations. 

In temperate climates females are most active on still, sunshiny days. 
It is unusual to find them flying on cloudy days or when strong wind is 
blowing. 

In taking a meal of blood a female Tabanus will usually insert and 
withdraw the beak several times, puncturing the skin of the host in a 
new place each time, before finishing the meal. The length of time 
occupied in taking a meal in cases observed by the writer has varied from 
about 3 to 11 minutes, and during this time the position may be changed 
5 or 6 times. Mitzmain has seen Tabanus striatus in the Philippines feed 
for 23 minutes. I have allowed~flies to bite my arm and feed to satiety. 
It is not a continuously painful process. The only part of the per- 
formance that is painful is the insertion of the beak, which takes but a 
few seconds. After that the drawing of the blood by the fly causes no 
sensation whatever in the arm. However, the habit of changing position 
so often during a meal is somewhat annoying. 

Horses are much more nervous under the attacks of Tabanus than 
cows. The latter often allow the flies to feed without much of any 
attempt to brush them off, but a horse fights constantly. Where the 
attack is severe, the horses in a pasture will bunch up together for 
mutual protection in rubbing against each other. Under such conditions 
it is possible that each fly will attack several horses, being brushed off 
several times before the meal is finished. This makes an ideal condition 



BIOLOGY AND HABITS OF HORSE FLIES 245 

for the spread of disease, if there are diseased animals in the herd. This 
habit of bunching up under fly attack applies also to cattle, where the 
attack is severe. 

I have never succeeded in obtaining any data on the number of blood 
meals a female will take. Mitzmain states that in the Philippines females 
of Tabanus striatum bite not oftener than once in % days. 



CONCERNING CONTROL MEASURES 

No universal remedy, or control measure, for horse flies can be given, 
owing to the diverse habits of the different species. In all cases, some 
knowledge of the life histories and habits of the species involved is 
necessary before any one can intelligently set in motion control measures, 
and I may say here that the life histories of very few species of Tabanus 
are now known. 

In some cases drainage of the larval habitat would undoubtedly be 
a good control measure. But the degree of drought resistance of the 
species in question should be ascertained before placing reliance upon 
this method of control. 

In Russia a species of Tabanus has the habit, in the adult form, of 
flying to water and dipping the abdomen. Porchinski, the Russian 
entomologist, advocates the oiling of the surface of the water as a con- 
trol for this species. It appears that Porchinski has used this method 
with good results. He applied the equivalent of a half pint of kerosene to 
six square feet of water surface. If this was not sufficient to do the work, 
a like amount was used the next morning. It must be borne in mind, 
however, that not all species of Tabanus have this dipping habit, and that 
in order to make the measure effective, the water would have to be com- 
paratively still, as otherwise the oil would soon pass off with the current. 

Occasionally the importation of egg parasites may be an effective 
control measure. At the present time, Tabanus punctifer in the Antelope 
Valley, Mono County, California, is apparently largely controlled by an 
unidentified hymenopterous egg parasite. 

Hine mentions the fact that in confinement small catfish eat the larvae 
of Tabanus stygius. It is possible that the stocking with catfish of 
streams inhabited with Tabanus larvae might have good results. 

In the way of protection of animals from the attacks of adult flies, 
various devices have been tried, such as nets, hoods, etc. In the Sierra 
Nevada Mountains, I found in one locality, a very useful horse hood in 
use to ward off the attack of Tabanus phaenops. This species attacks 
most viciously about the head and neck of horses. The hood is a simple 
arrangement made of light canvas to slip over the head and neck, with 
eye and breathing holes at the proper places. 



246 SANITARY ENTOMOLOGY 

Various repellents, mostly of an oily nature, have been tried as sprays, 
by different investigators, but none of these has proven very satisfactory 
as the effect is not lasting. 

BIBLIOGRAPHY 

Hine, J. S., 1903. — Tabanidae of Ohio with a Catalogue and Bibliography 
of the Species from America North of Mexico. Ohio State University 
Dept. Zool. and Ent., spec, paper, No. 5. 57 pp. 

Hine, J. S., 1904.— Tabanidae of the Western United States and Canada. 
Ohio State University, Contrib. Dept. Zool. and Ent., No. 21, pp. 
217-248. 

King, H. H., 1908. — Third Report of the Welcome Research Labora- 
tories, Gordon Memorial College, Khartoum. 

King, H. H., 1911. — Some Observations on the Bionomics of Tabanus 
ditaeniatus Macquart, and Tabanus kingi Austen. Bull. Ent. Re- 
search, vol. 1, pp. 265-274, fig. 7. 

Mitzmain, M. B., 1913. — The Biology of Tabanus striatus Fab., the 
Horse Fly of the Philippines. Philippine Journ. Sci., vol. 8 B, pp. 
197-222. 

Neave, S. A., 1915. — The Tabanidae of Southern Nyasaland with Notes 
on Their Life Histories. Bull. Ent. Res., vol. 5, pp. 287-320. 



CHAPTER XVII 

Diseases Transmitted by Mosquitoes 1 
IT". Dwight Pierce 

Probably more entomologists and sanitarians are familiar with the 
facts of mosquito transmission of disease than with any other phase of 
our subject, but a review of their role will not be amiss, especially as it 
will be presented in a different form from that usually adopted in text 
books. In this volume all of the chapters on disease transmission are 
handled in one manner, that is, by a systematic arrangement of the 
organisms transmitted. We may perhaps get a new conception of the 
relation of mosquitoes to parasitic organisms by this arrangement. Those 
organisms which are parasitic only need to be listed in order that 
students take into account the possibility of confusing them with the 
pathogenic organisms being sought. 

Teachers using these lectures as material for the study of their 
classes may find it of value to have the students make rearrangements 
of the subject by the name of the disease or the species of insects involved, 
or by the method of transmission. 

In our study of the non-bloodsucking flies we found that the disease 
transmission was principally through the feces, although also through 
the vomit, but never by direct inoculation. In the discussion of the 
bloodsucking flies it was shown that they usually transmitted disease 
while in the act of sucking blood. All known cases of disease transmission 
by mosquitoes are by direct inoculation at the time of the bite. In dengue 
fever the organism has not been demonstrated ; in malaria of all types we 
have a known organism which undergoes a definite life cycle in the mos- 
quito ; in filariasis we also have the mosquito serving as an intermediate 
host for the early stages of the worm. 

For complete studies of the life history of the malaria organism in 
the mosquito refer to Hindle (1914) in which you will also find lists of 
Anopheles of the world, with tables for identification, tables of malaria 
carriers and much more of a valuable nature, which should be carefully 
studied. Many other works deal very carefully with the subject, how- 
ever. The names of mosquitoes used in this and following lectures are on 
the authority of the late Frederick Knab. 

1 This lecture was presented August 19 and issued August 23, 1918, and has been 
more or less modified to its present form. 

247 



MS SANITARY ENTOMOLOGY 



DISEASES OF UNCERTAIN ORIGIN TRANSMITTED BY MOSQUITOES 

DENGUE FEVER, one of the severe fevers of the tropics, sometimes 
called break-bone fever, occasionally occurs in the United States. It is 
undoubtedly caused by a living organism which requires over two days 
to reach the stage necessary to produce the symptoms of the disease when 
inoculated into human beings. It is so small that it will pass through the 
pores of a filter which will retain Micrococcus melitensis, which is only 
0.4 micron in diameter. This minute organism is taken up by mosquitoes 
and transmitted to man. Graham-Smith and Ardate have observed small 
bodies in the red blood corpuscles, which are described as small, usually 
round, but sometimes elongate, bodies about one-fifth to one-third of the 
size of a red corpuscle. They divide up into minute granules, which 
become extra-corpuscular, and complete a cycle of schizogony. Graham 
(1903) fed Culex quinquefasciatus Say (fatigans Wiedemann), on dengue 
patients and claimed to have found his organism in the mosquitoes up to 
the fifth day after feeding. He succeeded, after an incubation period 
of four to six days, in infecting health} 7 people by the bites of mosquitoes 
fed on dengue patients in two series of experiments, claiming the trans- 
mission to be due to the Culex, but he states that Aedes argent eus Poirret 
(Stegomyia fasciata Fabricius) were present in many if not all of his 
experiments. Ashburn and Craig (1907) in the Philippines also claimed 
to have proved transmission by the bite of the same mosquito, but Cleland 
and Bradley (1918) challenge the results of both these investigations. 
Nevertheless, Bancroft (1906) conducted experiments obtaining two 
apparently successful cases of transmission of the disease by Aedes 
argenteus, ten and twelve days after these had bitten dengue patients, 
while in the three failures the test patients were bitten fifteen, fifteen and 
seventeen days after the mosquitoes fed on individuals suffering from 
dengue. 

Observations made by Legendre in Hanoi led him to suggest Aedes 
(Stegomyia) as probably a carrier of the virus. 

Cleland, Bradley, and McDonald (1918, 1919) conducted extensive 
experiments (1918) with both Culex quinquefasciatus {fatigans) and 
Aedes argenteus (fasciata) and obtained positive results with the latter 
in four out of seven tests, and negative results with the former in two 
tests. The mosquitoes after biting dengue patients were conveyed to dis- 
tricts where dengue fever did not exist. The incubation period in man in 
these cases was from six to nine and a half days. Later experiments 
(1919) corroborated this work. 

Poliomyelitis was experimented on with negative results by Howard 



\ 



DISEASES TRANSMITTED BY MOSQUITOES 249 

and Clark, using Culex pipiens Linnaeus, C. sollicitans Walker and C. 

cant at or Coquillett. 



PLANT ORGANISMS TRANSMITTED BY MOSQUITOES 

Tlialloplxyta: Fungi 

Myxococcidium stegomyiae Parker, Beyer and Pothier (1903) is a 
yeast normal to the mosquito Aedes argent eus (Stegomyia calopus 
Meigen). It was thought by its describers to be the causative organism 
of yellow fever, but this was disproven by the work of subsequent authors 
(Castellani and Chalmers, p. 1005). 

Thallophyta: Fungi: Schizomycetes: Bacteriaceae 

Bacterium anthracis Davaine, cause of ANTHRAX, was experimented 
upon with mosquitoes by Morris. Psorophora say'% (Dyar and Knab) and 
Aedes sylvestris (Theobald) Dyar and Knab commonly bite livestock in 
Louisiana and are very annoying. Out of 86 tests with these mosquitoes, 
feeding them on guinea pigs for different periods and at different times, 
from three hours before death to ten minutes after death, Morris obtained 
infection by the bite of the mosquito in 40 per cent of his tests. 

ANIMAL ORGANISMS TRANSMITTED BY MOSQUITOES 

Protozoa 
Mastigophora: Binucleata: Haemoproteidae 

Haemoproteus danilezcskyi (Grassi and Feletti 1890), cause of an 
AVIAN ANEMIA, passes its cycle of schizogony or asexual multiplica- 
tion in sparrows, larks, ravens, and birds of prey, and its cycle of spor- 
ogony or sexual multiplication in a species of Culex. It occurs in Europe, 
Africa. India, and America. 

Haemoproteus noctuae Celli and San Felice (1901), cause of an 
AVIAN AXEMIA, passes its cycle of schizogony in the owls, Glaucidium 
noctuae. Stria: iiammea, and Scops gin, and its cycle of sporogony in 
Culcx pipiens Linnaeus. Castellani and Chalmers (p. 295) give a detailed 
description of the life cycle as presented by Schaudinn, but in view of 
the fact that there is a belief tl^at Schaudinn has confused this species 
with a Trypanosoma we will omit discussion. It is supposed to occur in 
Europe. North Africa, and America. 

Haemoproteus symii Mauer (1910), cause of an AVIAN ANEMIA, 
passes its cycle of schizogony in the wood owl, Syrnium aluco, and its 
sporogony in the mosquito, Culiseta annulata Schrank (Theobaldia). 



250 SANITARY ENTOMOLOGY 

Mastigophora: Binucleata: Leucocytozoidae 

Leucocytozoon danilewskyi Ziemann (1898), cause of an AVIAN 
ANEMIA, passes its schizogony in the owls Glaucidium noctuae and Syr- 
nium aluco, and its sporogony in the mosquito Culex pipiens Linnaeus. 
The mosquito sucks up from the blood of the bird the gametocytes or pre- 
liminary stages of the sexual forms. These are taken into the stomach 
of the mosquito. The microgametocytes or male forms escape from their 
capsules, and the nuclei break up into eight double chromosomes, which are 
reduced to eight simple chromosomes. These travel to the periphery and 
form the microgametes. The macrogametocytes develop into macro- 
gametes. The gametes then conjugate and form the ookinetes, which 
are of three forms, male, female, and indifferent. These break up into 
very minute trypanosome-like bodies of the three forms which may divide 
by longitudinal fission. These are the forms which are inoculated into 
the owl by the bite of the mosquito. (See Castellani and Chalmers, p. 
303.) 

Mastigophora: Binucleata: Trypanosomidae 

Throughout this volume Chalmers' new classification of the Trypano- 
soma genera is adopted, as it gives an arrangement which most nearly 
corresponds to the biological relationships. 

Castellanella brucei (Plimmer and Bradford 1899) (Trypanosoma), 
the cause of NAGANA and JINJA, African animal diseases, is normally 
transmitted by species of Glossina, but Martin, Lehoeuf, and Roubaud 
(1908) successfully transmitted the disease from an infected to a healthy 
cat by a species of Mansonia. 

Castellanella evansi (Steel 1885) (Trypanosoma), the cause of 
SURRA in animals, is normally carried by biting flies, especially the 
Tabanidae, but Mitzmain (1914) records experiments with mosquitoes 
in which the parasite lived 42 hours in Aedes argent eus (calopus) and 30 
hours in Culex quinquefasciatus (fatigans) and C. ludlowi Blanchard. 

Castellanella gambiense (Dutton 1902) (Trypanosoma), the cause of 
GAMBIAN SLEEPING SICKNESS of man, is normally carried by 
tsetse flies of the genus Glossina, but Roubaud and Lafont (1914) gave 
experimental evidence that it can be transmitted by Aedes argenteus 
(Stegomyia calopus). Heckenroth and Blanchard (1913) succeeded in 
transmitting the disease by the bite of Mansonioides uniformis Theobald 
from guinea pig to guinea pig, when both were in the same cage, and also 
when not in contact, 24 hours after the mosquito had bitten the infected 
animal. 

Castellanella rhodesiense (Stephens and Fantham 1910) (Try- 
panosoma), the cause of RHODESIAN SLEEPING SICKNESS, is 



DISEASES TRANSMITTED BY MOSQUITOES 251 

normally carried by the tsetse flies of the genus Glossina, but Roubaud 
and Lafont (1914) have obtained experimental transmission with Aedes 
argent eus (Stegomyia calopus). 

Trypanosoma (sens, lat.) noctuae Schaudinn (1904), which may be 
confused with Haemoproteus noctuae Celli and San Felice, mentioned 
above, passes its schizogony in the owl, Glaucidium noctuae, and its 
sporogony in the mosquito, Culex pipiens. 

Trypanosoma (sens, lat.) ziemanni Schaudinn, another organism 
badly confused with T. noctuae and Leucocytozoon danilewskyi, is re- 
corded from Culex pipiens fed on the owl, Glaucidium noctuae. 

A Trypanosoma sp. was recovered by Durham from Aedes argent eus 
(Stegomyia fasciata) which had fed on bats (Phyllostomus sp.), and 
another Trypanosoma was recovered from a Culex by Mathis. 

Mastigophora: Binucleata: Leptomonidae 

Crithidia fasciculata Leger (1902) is a parasite of Anopheles maculi- 
pennis Meigen and Culex quvnquefasciatus (fatigans). Laveran and 
Franchini (1914) record Leishmania-form bodies, possibly of this species, 
in mice infected from Anopheles maculipennis. 

Leishmania brasiliensis Vianna (1911), the cause of ulcers known 
as BOUBA or ORAL LEISHMANIASIS of man in Southern Brazil and 
Northern Paraguay, is thought by Brumpt and Pedroso to be carried by 
Tabanidae or Culicidae. 

Leishmania donovani (Laveran and Mesnil 1903) is the cause of 
INDIAN KALA AZAR. It has been proven that the bedbug can carry 
it, but the normal carrier is unproven. Franchini (1911) fed Anopheles 
near claviger Fabricius on cultures of this organism and found that the 
parasite persisted and developed in the mosquitoes for at least 48 hours. 
Patton (1907) obtained no results in experiments with Culex quinque- 
fasciatus (fatigans), Stegomyia ingens and Anopheles stephensi Lis- 
ton. Mackie (1915) also failed in his experiments with Culex and 
Anopheles. 

Leishmania tropica (Wright 1903) is the cause of ORIENTAL 
SORE of man, which goes under various names, and it may really be a 
complex species. In investigating Bagdad sore Wenyon (1911a) fed 
Aedes argent eus (Stegomyia fasciata) on sores, and demonstrated in the 
mosquitoes the flagellate forms of the parasite up to 48 hours, but his 
transmission experiments failed. He later (1911b) succeeded in getting 
this mosquito to take up the parasites and demonstrated developmental 
stages in the gut. No evidence of infection could be found in experiments 
with Culex quvnquefasciatus (fatigans). 

Leptomonas algeriense Sergent and Sergent (1906) is parasitic in 
Culex pipiens and Aedes argent eus (calopus). 



252 



SANITARY ENTOMOLOGY 



Leptomonas cvlicis (Novy, MacNeal, and Torry, 1907) is native to 
Culex pipiens and Culex qumquefasciatus (fatigam). Fantham and Por- 
ter (1915, 1916) fatally infected birds by feeding them on infected in- 
sects, proving it experimentally pathogenic to Passer domesticus and 
Chelidon urbica. 

Mastigophora: Binucleata: Plasmodidae 

The Plasmodiums are the causative organisms of malaria, which are all 
carried by the bite of mosquitoes. The cycle of schizogony occurs in man, 



Host I (Man) 



Host E (Mosquito) 




I 

Cycle of Schizogony 
In Homo Sapiens (Man). 



Cycle of SporogoMV 
In Anopheles Spp. 



LIFE CYCLE OF PLASMODIUM 

The Cause of Pernicious Malaria. 
Fig. 47. (Pierce.) 

and of sporogeny in the mosquito (fig. 47). This life cycle is very clearly 
set forth in many textbooks and should be studied carefully by all stu- 
dents. Briefly it takes place as follows, starting with the minute sporo- 
zoite inoculated in man by the mosquito. This sporozoite is an elongate 
sickle-shaped body which bores into a red blood cell, and there forms an 
amoeboid shaped body known as the trophozoite, which gives off pseudo- 
podia that absorb nourishment from the cell. At first this trophozoite 
is of uniform mass, but soon a vacuole is formed, and it may assume a 
ring form. The trophozoite grows, withdraws its pseudopodia and be- 
comes a schizont. This divides into many merozoites, which burst the 
cell and escape into the blood stream. This completes the cycle of 
schizogony which may begin again by the merozoite entering a red blood 
cell and becoming a trophozoite. On the other hand it may develop into 






DISEASES TRANSMITTED BY MOSQUITOES 253 

a type of trophozoite which forms sexual bodies known as macrogame- 
tocytes and microgametocytes. These are the bodies which, when taken 
up by a mosquito, develop in the mosquito's body through the cycle of 
sporogony. In the stomach of the mosquito the microgametocytes divide 
into many tiny, elongate microgametes. The macrogametocytes change 
into macrogametes, and then conjugation of the gametes takes place. 
The resulting zygote is spherical, but it soon elongates into a small, worm- 
like body which is actively motile. It is then known as the ookinete. In 
this stage it bores into the epithelium of the gut wall and becomes rounded 
and thinly encysted. When encysted it is known as the oocyst. In this 
form it grows considerably in size and divides into sporoblasts, which 
divide into sporozoites. These tiny forms migrate into the salivary glands 
and are inoculated into a man at the time of a blood feast. 

The species of human malaria are Plasmodium vivace Grassi and 
Feletti (1892) causing the tertian disease, Plasmodium malaria Laveran 
(1881), causing the quartan disease, and Laverania falciparum (Welch, 
1897) (also known as Laverania malaria Grassi and Feletti, 1890, or 
Plasmodium falciparum), causing subtertian, malignant tertian, or 
aestivo-autumnal malaria. 

Many species of mosquitoes of the group Anophelinse have been 
charged with carriage of malaria but in many cases the evidence does not 
show what species of organism is carried. The evidence is briefly sum- 
marized below (see also Hindle, pp. 96-107). 

MALARIA OF UNKNOWN SPECIES.— The following species of 
mosquitoes are recorded as carriers or thought to be carriers of some form 
of malaria. These Anopheles are* often arranged in various subgenera, 
which are, however, omitted from our discussion. 

Anopheles aitkeni James (fragilis Theobald) is suspected as a malaria 
carrier by Daniels and Christophers (Hindle, p. 29). 

A. algeriensis Theobald was found by Sergent and Sergent in Al- 
geria to be a carrier in nature, the sporozoite state being found. 

A. apicimaculata Dyar and Knab has been suspected to be a carrier 
in Central America, but Darling records negative results. 

A. arabiensis Patton was found in nature carrying sporozoites by 
Patton in Aden Hinterland (Hindle). 

A. ardensis Theobald appears to Castellani and Chalmers (p. 665) 
as a probable carrier of malaria in Natal. 

A. boliviensis Theobald (lutzii Theobald) is suspected by Lutz to 
be a carrier in Brazil on what Knab (1913) considers insufficient 
grounds. 

A. braziliensis Chagas is cited by Brumpt (1913, p. 748) as a pos- 
sible carrier of malaria in Brazil. 



254 SANITARY ENTOMOLOGY 

A, const ani Laveran of Madagascar is listed as a malaria carrier 
by Castellani and Chalmers. 

A. culicifacies sergentii Theobald of Algeria is listed as a malaria 
carrier by Castellani and Chalmers. 

A. farauti Laveran is recorded as carrying malaria in the New 
Hebrides (Brumpt, p. 741). 

A. grabhamii Theobald, of the West Indies and South America, is 
listed by Castellani and Chalmers as a malaria carrier (p. 665). 

A. jamesii Theobald is listed by Castellani and Chalmers as a car- 
rier of malaria (p. 665). 

A. jeyporensis James is a carrier of malaria in India (Brumpt, p. 
746). 

A. karwari James and Liston was suspected by Staunton as a car- 
rier, but Christophers (1916) states that there is no evidence against 
it. 

A. maculipes Theobald is cited by Brumpt as a possible carrier in 
Brazil. 

A. martmi Laveran is regarded on epidemiological grounds by 
Laveran as a malaria carrier in Cambodia. (Castellani and Chalmers, 
p. 665.) 

A. mauritianus Grandpre (ziemanni Griinberg) is regarded by Ross 
as a doubtful carrier, not actively transmitting in Mauritius. Its 
synonym ziemanni is recorded by Castellani and Chalmers as a carrier 
in Africa. 

A. mauritianus paludis Theobald is recorded as a carrier in West 
Africa by Castellani and Chalmers. 

A. minimus Theobald (febrifer) is according to Walker and Barber 
(1914', the most important mosquito concerned in the epidemiology of 
malaria in the Philippines, being susceptible to infection and having a 
high avidity for blood. 

A. minimus Christopher si Theobald is recorded by Castellani and 
Chalmers as a carrier in India. 

A. nimba Theobald of Brazil is listed by Castellani and Chalmers 
as a carrier. 

A. pitchfordi Tower of Africa is recorded as a probable carrier by 
Castellani and Chalmers. 

A. punctulata Donitz is listed as a carrier in New Guinea by Cas- 
tellani and Chalmers. 

A. pursati Laveran is considered by Laveran on epidemiological evi- 
dence a carrier in Cambodia. 

A. rhodesiensis d'thali Patton at Aden is cited as a possible carrier 
by Patton (Hindle). 



DISEASES TRANSMITTED BY MOSQUITOES 255 

A. sinensis pseudopictus Grassi is recorded by Castellani and Chal- 
mers as a carrier in Italy. 

A. turkhudi chaudoyei Theobald of Algeria is recorded by Castellani 
and Chalmers as a carrier. 

A. turkhudi myzomyifacies Theobald was taken in nature carrying 
sporozoites of Plasmodium in Algeria by Sergent and Sergent (Hindle). 

A. vincenti Laveran is recorded by Laveran as a carrier in Tonkin 
(Castellani and Chalmers). 

A. willmori James of Tonkin was taken by Mrs. Adie in nature carry- 
ing sporozoites of Plasmodium (Hindle). 

Of the above list we may consider therefore as proven malaria car- 
riers algeriensis, arabiensis, minimus, turkhudi myzomyifacies, and will- 
mori. In the other cases the evidence is not sufficient. 

SUBTERTIAN MALARIA. — Caused by Laverania falciparum 
Welch (1897) (Laverania malaria Grassi and Feletti 1890). This fever 
is also called tertian aestivo-autumnal and malignant tertian malaria. 
Records of transmission have been made for the following mosquitoes : 

Anopheles albimanus Wiedemann (albipes Theobald) is the common- 
est carrier in Central and Tropical South America. Seventy per cent of 
those fed by Darling (1910) became infected. He traced development to 
the sporozoite stage. 

A, amnulipes Walker, a common Australian species, has been shown 
by Kinoshita to carry this organism. 

A. argyrotarsis Robineau-Desvoidy is regarded as an undoubted car- 
rier by Knab (1913) and Ludlow (1914) in the West Indies and South 
America. Although Darling found zygotes in nature, Hindle questions 
the species of organism. 

A. barbirostris Van der Wulp of India, Malaysia, and China was 
recorded as carrier by Stephens and Christophers (Hindle). 

A. costalis Loew was shown by Ross, Annett, and Austen (1900) to 
carry this organism in Tropical Africa. 

A. crucians Wiedemann was definitely proven a carrier in Louisiana 
by King (1916) who found oocysts and sporozoites in his experimentally- 
fed mosquitoes. He found 75 per cent of his mosquitoes infected. 

A. culicifacies Giles was shown by Stephens and Christophers to be 
the commonest Indian carrier. 

A. formosaensis II Tsuzuki was found to be a carrier in Formosa by 
Tsuzuki (1902) who proved the presence of sporozoites. 

A. fuliginosus Giles was shown to be the carrier in India by Stephens 
and Christophers who demonstrated zygotes in the mosquito. 

A. funestus Giles is an active and important malaria carrier in 
Tropical Africa, its connection with this organism being demonstrated 
by Daniels. 



256 SANITARY ENTOMOLOGY 

A. maculatus Theobald is a common carrier in India and the Malay 
States, its relation to this organism being shown by Staunton. 

A. maculipalpis indiensis Theobald a common carrier in Northwest 
Terai, India, was proven a carrier by Stephens and Christophers who 
demonstrated zygotes. 

A. maculipennis Meigen is the common malaria carrier in Europe, 
proven by many authors since Grassi. 

A. minimus aconitus Donitz and its synonyms albirostris Theobald, 
coheesus Donitz, and formosaensis I Tsuzuki, has been shown to be a car- 
rier of malaria in Malaysia and India. Staunton proved the carriage of 
this organism by albirostris and Tsuzuki by formosaensis I. 

A. pseudopunctipennis Theobald (franciscanis McCracken) was 
proven a carrier in Panama by Darling (1910) who found zygotes in his 
experimental mosquitoes. 

A. punctipennis Say was first proven a carrier of this organism 
in Louisiana by King (1916) who found 20 per cent of his experimental 
mosquitoes infected, and later Mitzmain (1917) corroborated this by 
finding 27 per cent of his experimental mosquitoes infected. 

A, quadrimaculatus Say was first proven a carrier of this organism 
in the United States by Thayer (1900), and later corroborated by Wol- 
dert in 1901, and Hirshberg (1904), and finally by King (1916) who 
found 23 per cent of his mosquitoes, fed on a certain case, infected. 

A. rossii Giles was shown by Stephens and Christophers to be a car- 
rier in India, but not commonly. 

A. sinensis Wiedemann of Southeastern Asia was recorded as a car- 
rier by Christophers (1916). 

A. tarsimaculatus Goeldi was found by Darling (1910) in Panama 
to be infected in 100 per cent of his experiments with this organism. 

A. theobaldi Giles was shown to be a carrier in India by Stephens 
and Christophers, who demonstrated zygotes in the experimental mos- 
quitoes. 

A. turkhudi Liston was shown to be a carrier in India by Stephens 
and Christophers, who demonstrated zygotes in the experimental mos- 
quitoes. 

A. umbrosus Theobald was shown to be a carrier in the Malay 
States by Staunton, who demonstrated zygotes in the experimental mos- 
quitoes. 

For American students of-aestivo-autumnal or subtertian malaria, the 
following species are therefore of importance — albimanus, argyrotarsis, 
crucians, pseudopunctipennis, punctipennis, quadrimaculatus, and tar* 
simaculatus. For those of our troops who go abroad the other species 
listed above are of greater importance. 

QUARTAN MALARIA.— This type of malaria is caused by Plas- 



DISEASES TRANSMITTED BY MOSQUITOES 257 

modium malariae Laveran (1881). The following species of mosquitoes 
have been proven to be carriers : 

Anopheles algeriensis Theobald was proven by Sergent and Sergent 
(1906) to be a carrier in Algeria. 

A, cost alls Loew was shown by Ross, Annett, and Austen (1900) to 
be a carrier in Africa. 

A, culicifacies Giles is the most common Indian carrier and its rela- 
tionship to this organism was proven by Stephens and Christophers. 

A. fuliginosus Giles is not an active carrier in India but Stephens and 
Christophers demonstrated the zygotes of this organism. 

A. funesta Giles is an active and important carrier in Africa, its 
role being proven by Ross, Annett, and Austen (1900). 

A. maculipenmis Meigen is the common European carrier. 

A. myzomyifacies Theobald is a carrier in Algeria according to Ser- 
gent and Sergent (1906). 

A. quadrimaculatus Say was proven a carrier in the United States by 
Beyer, Pothier, Couret, and Lemann (1902). 

A. rossii Giles was proven capable of transmitting this organism in 
India by Stephens and Christophers. 

A. sinensis Wiedemann was shown to be a carrier in China and South- 
eastern Asia by Tsuzuki. 

A. stephensi Liston is claimed to be a carrier in India by Christophers 
(1916). 

A. theobaldi Giles was proven a carrier in India by Stephens and 
Christophers, who demonstrated zygotes in experimental mosquitoes. 

Thus it will be seen that onty one species of mosquito in America, 
quadrimaculatus, has been demonstrated to be a carrier of quartan 
malaria. 

TERTIAN MALARIA. — Tertian malaria is caused by Plasmodium 
vivax Grassi and Feletti (1892). It has been shown to be carried in 
various parts of the world by the following mosquitoes: 

Anopheles albimanus Wiedemann was found to be a common carrier 
in Panama by Darling (1910), who demonstrated zygotes and sporo- 
zoites. 

A. barbirostris Van der Wulp is recorded by Christophers (1916) as 
a carrier in India. 

A. bifurcatus Linnaeus is recorded as a carrier in Europe by Grassi. 

A. costalis Loew was shown by Ross, Annett, and Austen to be a car- 
rier in Africa. 

A. crucians Wiedemann was proven by Mitzmain (1916) to be capable 
of carrying this organism in Louisiana. Sporozoites were obtained. 

A. culicifacies Giles is recorded as the commonest carrier in India 
by Stephens and Christophers. 



258 SANITARY ENTOMOLOGY 

A. fuliginosus Giles is recorded as a carrier in India by Christophers 
(1916). 

A. funesta Giles is the most active and important common carrier 
in Africa according to Ross, Annett, and Austen. 

A. intermedium Chagas is a carrier in Brazil according to Cruz. 

A. jesoensis Tsuzuki is recorded as a carrier by Christophers (1916). 

A. listoni Liston is an active and important carrier in certain terai 
tracts in India, recorded by Kinoshita. 

A. macvlatus Theobald is recorded as a carrier in India by Chris- 
tophers (1916). 

A. maculipalpis Giles is recorded as a carrier in Asia by Christophers 
(1916). 

A. maculipennis Meigen is a common carrier in Europe. 

A. medio punc tat us Theobald is a carrier in Brazil according to Cruz 
(1910). 

A. minimus Theobald is recorded as a carrier in India by Christo- 
phers (1916). 

A. pharoensis Theobald is recorded as a carrier in Egypt by New- 
stead, Button, and Todd (1907). 

A. pseudomaculipes Chagas is' recorded as a carrier in Brazil by Cruz 
(1910). 

A. punctipennis Say was first proven a carrier in the United States 
by King (1916). Sporozoites were found. Later Mitzmain (1916) cor- 
roborated this record. 

A. quadrimaculatus Say was first proven a carrier in the United 
States by Thayer (1900). This was subsequently proven by other 
authors, including King (1916). 

A. rossii Giles is recorded as a carrier in India by Christophers 
(1916). 

A. sinensis Wiedemann is recorded as a carrier by Kinoshita in 
China. 

A. stephensi Liston is recorded as a carrier in India by Liston and 
by Bentley. 

A. superpictus Grassi is recorded as a carrier in Europe by Grassi 
and by Bignami and Bastianelli. 

A. theobaldi Giles is recorded as a carrier in India by Christophers 
(1916). 

A. turkhudi Liston is recorded as a carrier in India by Christophers 
(1916). 

A. turkhudi hispaniola Theobald is a common carrier in Algeria and 
Southern Spain according to Sergent and Sergent. 

Thus we find tertian malaria in America carried by albimanus, cru- 



DISEASES TRANSMITTED BY MOSQUITOES 259 

dans, intermedium, medio punc tat us, pseudomaculipes, punctipennis, and 
quadrimaculatus, three of which species occur in the United States. 

AVIAN MALARIA. — Several forms of avian malaria are known. 

Plasmodium danilewsky Grassi and Feletti (1890), a malaria of spar- 
rows, partridges, finches, and crows is carried by Culex quinquefasciatus 
(fatigans), C. pipiens, Aedes nemorosus Meigen, and A. argenteu\s 
(calopus) according to various textbooks. 

Plasmodium relictum, a malaria of the canary, was proven by Sergent 
and Sergent (1918) to be carried by Culex pipiens. 

Mastigophora: Spirochaetacea: Spirochaetidae 

Spirosckaudinnia culicis Jaffe (1907) was found by Jaffe in the 
gut and malpighian tubules of Culex pipiens and Anopheles maculi- 
pen/nis. 

Leptospira icteroides Noguchi (1919) has been proven to be the 
causative organism of YELLOW FEVER in investigations made in 
Ecuador. Noguchi obtained pure cultures by inoculation of guinea pigs 
with blood of yellow fever patients. He isolated the organisms from 
three patients and also from mosquitoes and inoculated them into guinea 
pigs, dogs, and marmosets {Midas oedipus and M. geoffroyi). The 
organism is filterable. 

This dread disease of the tropics has been studied for }^ears and 
many other investigators have sought the organism without success. Sei- 
delin, in 1909, described a parasite belonging to the Babesiidae in the 
blood and organs of yellow fever patients, as Paraplasma flavigenum, 
which he considered to be the cause of yellow fever, but this organism 
was not generally accepted as the causative organism. The incubation 
period in man is three days and the mosquito to become infected must bite 
a patient during the first three days of his illness, and then twelve days 
must elapse before the infected mosquito can transmit the disease to man. 

The organism of yellow fever may pass through the pores of a Pasteur 
Chamberlain B. filter. The disease can be conveyed by subcutaneous in- 
jection of the blood taken from the general circulation of a person sick 
with the disease during the first three days of the disease, but can be 
carried naturally only by the bite of a mosquito (Aedes argent eus, usually 
called Stegomyia fasciata), that at least 12 days before has fed on the 
blood of a person sick with this disease, during the first three days of his 
illness. But Noguchi transmitted it by the bite of a mosquito from a 
diseased to a healthy guinea pig in 8 days and 8-12 days, and from man 
to guinea pig, 23 days after biting'man. Prophylaxis therefore consists 
in prevention of biting by mosquitoes, and mosquito extermination. 

There is no definite proof that the virus can be transmitted heredita- 



260 SANITARY ENTOMOLOGY 

rily in the mosquito. There is indication of a granular stage of develop- 
ment. The optimum temperature for development is 26° C. 

The earliest suggestions of the possibility of mosquito carriage of 
yellow fever were made by Josiah C. Nott in 1848, and Dowler in 1855. 
In 1881 Dr. Carlos J. Finlay made definite claims that the fever is car- 
ried by the bite of a mosquito. In 1900 during the American occupation 
of Cuba a commission composed of Doctors Walter Reed, James Car- 
roll, Aristides Agramonte, and Jesse W. Lazear began the investigation 
of the causation of yellow fever by first definitely discrediting the theory 
of the Italian bacteriologist, Dr. Giuseppe Sanarelli, that his Bacillus 
icteroides was the cause. This they proved to be identical with Bacillus 
sui-pestifer. They then conferred with Dr. Finlay and began a thorough 
investigation of the mosquito transmission theory. Dr. Finlay suggested 
the common house mosquito, Aedes argent eus (Stegomyia fasciata) as 
the cause. The members of the commission submitted themselves to the 
making of the tests. Dr. Carroll was the first to take the fever, being 
bitten twelve days after a mosquito had bitten a yellow fever patient. 
In four days he took the fever. A week later Dr. Lazear, while conduct- 
ing experiments, was bitten by a mosquito, which he allowed to engorge, 
but to which he paid little attention. In five days he took the fever and 
died in a week. In the course of experiments ten cases of fever were pro- 
duced at will by the application of infected mosquitoes, and all other 
possible means of infection proved useless (see Reed, etc.). 

Dr. Guiteras (1901) confirmed the transmission of yellow fever by 
Aedes argent eus {Stegomyia fasciata) in seven cases, three of which 
proved fatal. Later a French commission, Marchoux, Salimbeni and 
Simond (1903) in Brazil, and American commissions composed of Parker, 
Beyer, and Pothier in Mexico (1903), and Rosenau, Parker, Francis, 
and Beyer (1905), corroborated the transmission of the disease by this 
mosquito. The last named authors tabulate the whole series of trans- 
mission experiments showing that in 40 cases of transmission by mos- 
quito bite, the incubation period after the bite exceeded three days and a 
fraction in only ten cases, and was possibly less than three whole days 
in only two cases. The maximum authentic record of the incubation 
period is six days and two hours. 

Metazoa 

Platyhelmia: Fasciolidae 

A Clinostomum is recorded by Soparker (1918) which passes its 
first stage in a snail, Planorbis eocustus, and is found as a cercaria in the 
larvae and adults of Culeoc quinquefasciatus (fatigans) and Anopheles 



DISEASES TRANSMITTED BY MOSQUITOES 261 

rossii. Fish swallowing the mosquito larvae take up the worm, which 
continues its development toward maturity. The final host is not 
known. 

Nemathelminthes: Nematoda: Filariidae 2 

Acanthocheilonema perstans (Manson 1891), the cause of a form of 
human FILARIASIS in Africa, is probably carried by biting flies. 
Hodges in Uganda obtained an incomplete cycle in Mansonioides africanus 
Theobald (Panoplite), Aedes argenteus (calopus), A. sugens Wiedemann, 
Anopheles costalis Loew, and a Culex, and negative results with a long 
series of mosquitoes (Dye, 1905). Low (1903) obtained incomplete de- 
velopment in T aeniorhynchus fuscopennatus. 

Dirofilaria immitis (Leidy, 1856), cause of CANINE FILARIASIS, 
has been proven by Noe, Dye (1908), Grassi, and Fiilleborn (1912) to 
pass its intermediate stages in the following mosquitoes — Anopheles 
maculipeninis Meigen (claviger Fabricius), A. algeriensis Theobald, A. 
hifurcatus Linnaeus, A. sinensis Wiedemann (pseudopictus Grassi), A. 
super pictus Grassi, Culex quinquefasciatus Say (fatigans Wiedemann), 
C. malarice Grassi, C. penicillaris Rondani, and Aedes vexans Meigen 
(Culex) exceptionally in C. pipiens, and with difficulty in Aedes argenteus 
(Stegomyia calopus). The microfilaria or embryo worms are taken up 
by the mosquito with the blood of the dog. They soon pass from the 
stomach into the Malpighian tubules. In ten days their development is 
complete and they migrate towards the head and into the proboscis. 
When an infected mosquito containing filariae in its proboscis feeds on a 
dog, the worms escape by boring through a delicate membrane which 
unites the labellae, and thus get on the surface of the skin. If this is suf- 
ficiently moist they penetrate the epidermis and may be found in the sub- 
cutaneous tissues, whence they work toward the heart and great vessels 
of the dog and there develop into adults. 

Dirofilaria repens Railliet and Henry (1911), cause of SUB- 
CUTANEOUS CANINE FILIARIASIS, passes its intermediate stages 
in the mosquito Aedes argenteus, its development having been demon- 
strated b}' Bernard and Bauche (1913). Its life history is quite similar 
to that of D. immitis. 

Filaria bancrofti Cobbold (1877), the cause of HUMAN FILARIA- 
SIS or ELEPHANTIASIS, passes its intermediate stages in the mos- 
quitoes. Complete development has been demonstrated in Anopheles rossi 
Giles in India by James; A. costalis Loew in West Africa by Annett, 
Dutton, and Elliot ; Culex pipiens in China by Manson ; C. quinquefascia- 
tus Say (fatigans Wiedemann, ciliaris Bancroft, nigrithorax skusei Giles) 
in China by Manson, in South Carolina by Francis, in Australia by Ban- 
2 For further discussion of the following worms see Chapter V. 



262 SANITARY ENTOMOLOGY 

croft, in the West Indies by Lebredo (under the name pipiens) and also 
by Law, in the Philippines by Ashburn and Craig, and in India by Cruik- 
shank and Wright; Aedes pseudoscutellaris Theobald in Fiji; Man- 
sonioides africanus Theobald by Daniels in Nyasaland; M. uniformis 
Theobald, and Aedes argent eus Poirret (Stegomyia calopus Meigen, A. 
fasciata Fabricius, Culex taeniatus Meigen) in Nigeria by Daniels, and 
in the West Indies by Law. 

Complete development has not been demonstrated as forms have not 
been actually seen in the proboscis, although advanced stages have been 
recorded in Anopheles sinensis Wiedemann (mmutus Theobald, pseudopic- 
tus Grassi, peditaeniatus Leicester, nigerrimus Giles) and barbirostris 
Van der Wulp in Malaysia by Leicester; A. argyrot arsis Robineau-Des- 
voidy in West Indies by Law; A, albimanus Wiedemann (albipes Theo- 
bald) in West Indies by Vincent; Mansonioides annulipes Theobald in 
Malaysia by Leicester, and in Australia by Bancroft ; Mansonia pseudo- 
titillans Theobald ; Culex microannulatus Skuse ; C. gelidus Theobald, and 
C. sitiens Wiedemann, Aedes perplexa Leicester, A. scutellaris Walker, 
Scutomyia albolmeata Theobald and Taeniorhynchus domesticus Leices- 
ter in Malaysia by Leicester. 

Francis (1919) reports absolutely negative results with Aedes 
argenteus (calopus) in South Carolina. 

The embryo microfilaria enter the mosquito's stomach with the blood. 
They rupture the sheaths which contain them, pierce the walls of the 
stomach and find their way to the muscles of the thorax, where they 
develop. They finally work into the proboscis and escape during the act 
of feeding, through Dutton's membrane, as worked out by Lebredo (1905). 
They enter the skin through the bites or through pores. 

Filaria demarquayi Manson (1897), another cause of HUMAN 
FILARIASIS, was found by Fiilleborn to pass its immature stages in 
the thoracic muscles of Aedes argenteus (calopus). Mense also records 
Culex quinquefasciatus and Anopheles albimanus as hosts. 

Nemathelminthes: Nematoda: Mermithidae 

Agamomermis culicis Stiles (1903) is recorded from Culex sollicitans 
Walker in the United States. 

From a purely American standpoint we must guard against mos- 
quitoes as carriers of malaria, yellow fever, dengue, and filariasis, but 
troops operating in Mediterranean countries would also have to consider 
possible transmission of tropical sores and Kala Azar. In South America 
other forms of sores ; in Africa sleeping sicknesses may be carried by 
mosquitoes. 

The burden of all this evidence is that mosquitoes should not be 



DISEASES TRANSMITTED BY MOSQUITOES 263 

permitted to breed near human habitations, and especially near Army 
establishments. 

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264 SANITARY ENTOMOLOGY 

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Laveran, A., and Franchini, G., 1914. — Bull. Soc. Path. Exot., vol. 7, 

pp. 605-612. 
Law, G. C, 1903.— Brit. Med. Journ., vol. 1, pp. 722-724. 
Lebredo, M. G., 1905. — Journ. Infect. Diseases, Suppl. No. 1, pp. 332- 

352. 
Ludlow, C. S., 1914.— U. S. War Dept., Office Surgeon Genl., bull. 4, 

pp. 1-94. 
Mackie, F. P., 1915. — Indian Journ. Med. Research, vol. 2, pp. 942- 

949. 
Marchoux, E., Salimbeni, A., and Simond, P. L., 1903. — Rapport de 

la Mission Francaise, Ann. Inst. Pasteur, November, vol. 17, pp 

665-731. 
Martin, G., Leboeuf, and Roubaud, E., 1908.— Bull. Soc. Path. Exot. 

vol. 1, pp. 355-358. 
Mitzmain, M. B., 1914.— U. S. Treas. Dept., Hygienic Lab., bull. 94 
Mitzmain, M. B., 1916.— Public Health Reports, May 12, pp. 1172-1177 
Mitzmain, M. B., 1917.— Public Health Reports, July 6, pp. 1081-1083 
Morris, H., 1918. — Louisiana Agr. Exp. Sta., bull. 163, 11 pp. 
Noguchi, H., 1919. — Journ. Amer. Med. Assoc, vol. 72, No. 3, pp 

187-188. 
Noguchi, H., 1919.— Journ. Exper. Med., vol. 29, No. 6, pp. 547-596 

vol. 30, No. 1, pp. 1-29; No. 2, pp. 87-107; No. 4, pp. 401-410. 
Parker, H. B., Beyer, G. E., and Pothier, O. L., 1903.— U. S. Publ 

Health & Marine Hosp. Serv., Yellow Fever Institute, bull. 13, 48 pp 
Patton, W. S., 1907.— Scient. Mem. Officers Med. and Sanit. Depts. 

Govt. India, n. s., Nos. 27, 31. 
Reed, Walter, 1901.— Am. Med., July 6. 

Reed, Walter, and Carroll, J., 1902. — Am. Med., vol. 3, February 22. 
Reed, W., Carroll, J., Agramonte, A., and Lazear, J. W., 1900. — Phila. 

Med. Journ., Oct. 27, vol. 6, pp. 790-796. 
Reed, W., Carroll, J., and Agramonte, A., 1901. — Journ. Am. Med. 

Assoc, February 16, vol. 36, pp. 431-440. 
Rosenau, M. J., Parker, H. B., Francis, E., and Beyer, G. E., 1904. — 



DISEASES TRANSMITTED BY MOSQUITOES 265 

U. S. Publ. Health & Marine Hosp. Serv., Yellow Fever Inst., bull. 

14, pp. 49-101. 
Ross, R., Annett, H. E., and Austen, E. E.,1902. — Report of the Malaria 

Expedition of the Liverpool School of Tropical Medicine, Liverpool 

Sch. Trop. Med., Memoir 2, pp. 1-58. 
Roubaud, E., and Lafont, A., 1914. — Bull. Soc. Path. Exot., vol. 7, No. 

1, pp. 49-52. 
Sergent, Ed. and Sergent, Et., 1906. — Ann. Inst. Pasteur, vol. 20, pp. 

241-255, 364-388. 
Sergent, Ed. and Sergent, Et., 1918.— Bull. Soc. Path. Exot., vol. 11, 

No. 4, p. 281. 
Soparker, M. B., 1918. — Indian Journ. Med. Research, vol. 5, No. 3, 

pp. 512-515. 
Staunton, 1913. — Journ. London School Trop. Med., vol. 2. 
Stephens, J. W. W., and Christophers, S. R., 1908.— The Practical 

Study of Malaria, University Press, Liverpool School Trop. Med., 

pp. 1-414. 
Stephens, J. W. W., and Christophers, S. R., 1899-1902.— Reports to 

the Malaria Committee of the Royal Society. Nos. l,to 8. 
Thayer, W. S., 1900.— Philadelphia Med. Journ. vol. 5, pp. 1046-1048. 
Tsuzuki, J., 1902.— Arch. f. Schiff's- u. Trop. Hyg., vol. 6, pp. 9, 

285-295. 
Walker, E. L., and Barber, M. A., 1914. — Philippine Journ. Science, 

Manila, vol. 9B, No. 5, pp. 381-439. 
Wenyon, C. M., 1911a.— Kala Azar Bull., vol. 1, pp. 36-58. 
Wenyon, C. M., 1911b.— Parasitology, vol. 4, No. 3, pp. 273-344. 



CHAPTER XVIII 

What We Should Know About Mosquito Biology * 
W. Dwight Pierce and C. T. Greene 

Entomologists are generally better informed about the life history 
of mosquitoes than of most of the insects which carry disease. It is 
therefore more essential a!: this time to sketch over some of the points 
to which we as sanitary entomologists must pay attention. .Any one 
studying mosquitoes must, before completing his study, digest the won- 
derful mass of material in Howard, Dyar, and Knab's Monograph, espe- 
cially volume 1. 

All mosquitoes pass their early stages in water. They cannot develop 
in any other medium. 

The adult mosquito is known to every one, but its eggs deposited 
on the water are the least known. The larvae, commonly known as wiggle- 
tails, and the peculiar shaped pupae are fairly well known. 

The different species of mosquitoes are more or less selective as to 
the type of water in which they breed, and careful study of mosquito 
habitats is essential to all who have to do with mosquito sanitation. 
Therefore we must, at least in this lecture, consider the habits of all our 
American disease-carrying mosquitoes. Many of the others may be 
capable of carrying disease, but no proof has been brought forward 
against them. 

In the preceding lecture it was shown that the following mosquitoes 
of the United States are disease carriers : 

Dengue fever is carried by Culex quinquefasciatus (fatigans), and 
Aedes argent eus (Stegomyia calopus or fasciatus). 

Yellow fever is carried by Aedes argent eus. 

Subtertian or aestivo-autumnal malaria is carried by Anopheles 
crucians, pseudo punctipennis, punctipennis, and quadrimaculatus. 

Quartan malaria is carried by Anopheles quadrimaculatus. 

Tertian malaria is carried by Anopheles crucians, punctipennis and 
quadrimaculatus. 

Filariasis is carried by Culex quinquef asciatus and Aedes argent eus. 

These six species of mosquitoes are then the ones most to be feared 

'This lecture was presented to the class September 16, 1918. 

266 



WHAT WE SHOULD KNOW ABOUT MOSQUITO BIOLOGY 267 

in our own country. One traveling in other countries must guard 
against entirely different species. 



OVIPOSITION AND THE EGG STAGE 

Mosquitoes lay their eggs in various ways. The mode of deposition 
best known is that of laying all the eggs at once in a so-called raft. 
The eggs are cylindrical, rounded at the ends and tapering toward the 
upper end. They are placed in an upright position and fastened together 
by a viscous secretion. They are deposited upon the water or near it. 
Such is the type of oviposition of Culex and several other genera. 

Some mosquitoes, as Culex jenningsi, surround the eggs with a gelat- 
inous mass which furnishes the first food to the newly-hatched larvae. 

The various species of Anopheles deposit the eggs separately in small 
numbers on the surface of the water. The eggs lie upon their sides and 
are kept afloat by a peculiar hydrostatic organ, a partial envelope which 
is more or less expanded, particularly along the median portion of the 
egg. This organ is variously shaped in the different species of Anopheles 
and is called a float. 

Of the mosquitoes which lay single eggs, some fasten them by a 
gelatinous substance at the margin of the water, others lay them on 
the ground where they remain until rains provide sufficient moisture for 
hatching. Some of these eggs are enabled to float because of spinose 
tubercules which hold the air between them. The species of Aedes lay 
their eggs singly and not all at once. It often happens that eggs laid 
in the summer in northern latitudes lay over to the next spring. 

Aedes argent eus Poirret, the yellow fever mosquito, lays eggs meas- 
uring 0.53 mm. long and 0.15 mm. in diameter. They are black, fusiform, 
very slightly flattened on one side, slightly more tapered toward the 
micropylar end; sculptured with rough, somewhat irregular rhomboidal 
callosities forming spiral rows. Under natural conditions the eggs are 
laid singly in small irregular groups some distance above the margin 
of the water. They are laid in from one to seven da} r s after the female has 
fed upon blood, and usually at intervals after successive blood meals. 

Culex quvnquefasciatus Say, the dengue fever mosquito, lays its eggs 
in boat-shaped masses floating on the surface of the water. It may lay 
from 180 to 350 in a mass in 7 to 11 rows. The eggs hatch after one to 
three days. An egg mass of a Culex mosquito is shown in fig. 48. 

Anopheles crucians Wiedemann has an elongate fusiform egg 
(fig. 49c) slightly more tapered toward one end, both ends rounded. 
The dorsal surface is granular, the ventral surface coarsely hexagonally 
reticulate. The floats occupy about half the sides in top view, and arc 
separated at the middle by nearly one-third the diameter of the egg. 



268 



SANITARY ENTOMOLOGY 



These eggs are laid singly, a small number at a time, upon the surface of 
the water. 

Anopheles punctipennis Say (fig. 49a) has an elongate fusiform egg y 
reticulate ventrically, finely granular dorsally. The floats are large, 
extending nearly to the apices, closely approximated medianly on the 
dorsal surface, arcuately produced at the sides to the apical fourths, 




Fig. 48. — Eggs and larvae of Culex. Enlarged. (Howard.) From U. S. Dept. Agr., 

Farmers' Bull. 155, fig. 5. 

widely separated on the ventral surface, and showing only on middle 
third of sides. The eggs are laid singly or in small groups upon the 
surface of the water. 

Anopheles quadrimaculatus egg is shown in fig. 49b. 



THE LARVAE AND THEIR HABITS 



All mosquito larvae are aquatic. By far the most of the larvae occur 
in small deposits of water, although certain species occur in large bodies 





Fig. 49. — Eggs of malaria mosquitoes: a, Anopheles punctipennis; b, A. quadrimacula- 
tus; c, A. crucians. (After Howard, Dyar and Knab.) 

of water. Those species which lay their eggs on the ground in dry 
regions, hatch as soon as rains occur, and the larvae go through a very 
rapid development. Such species show a rather marked periodicity in 
broods. Species which have abundance of water breed continuously 
during the warmer seasons. One is apt to find mosquito larvae wherever 
water occurs. 

The food of the larvae varies, but usually consists of the minute forms 



WHAT WE SHOULD KNOW ABOUT MOSQUITO BIOLOGY 269 

of plant and animal life in the water, although certain species are 
predaceous, and some are scavengers upon the dead animals and insect 
life in their habitat. 

The larva? of mosquitoes are very peculiarly constructed. The mouth 
is furnished with tufts of filaments which are constantly in vibration. The 
head is large, the antenna? long, the thorax somewhat swollen, and the 
abdomen slender. The sides of the body are furnished with stiff bristles. 
From the next to the last segment there protrudes a long tube nearly as 
thick as the body itself, and it is this tube that touches the surface of 
the water when the larva rises to breathe. When in this position the 
larva ranges downward in various attitudes characteristic of the species. 
The object of this tube is to get air. At the extremity is a breathing 
hole, or spiracle, and into it run two main trachea? which extend through 
the body of the insect with many branches which carry air to all parts 




In fa InM 



Fig. 50. — Larva of the vellow-fever mosquito. Much enlarged. (Howard.) From U. S. 
Dept. Agr., Office Secy., Cir. 61, fig. 14. 



of its tissues. The true anal end of the body is furnished with four more 
or less developed tracheal gills. 

When suspended from the surface the wriggler's mouth parts are 
constantly in vibration, bringing into its mouth any minute particles 
which float in suspension in the water. 

It is when the larva extends its breathing tube from the surface of 
the water that it offers the greatest opportunity for control. All efforts 
to maintain an oil film on the surface of the water are aimed at clogging 
up this tube when it comes to the surface, and thus cutting off the air 
supply. 

Occasionally the larva descends to the bottom, jerking its body vio- 
lently from side to side. The anal tracheal gills undoubtedly assist in 
this motion. The larva 3 are active and move backward through the water 
by these jerky movements. They can move slowly forward by the action 
of the mouth brushes. Some species are specially equipped for obtaining 
air from the water or from plants and do not come to the surface. This 
is fortunately not the case with those we are most interested in. 

Aedes argent eus larva (fig. 50) has the head rounded, widest behind 
the eves. The thorax is rounded, wider than loner, with moderate, rather 



270 SANITARY ENTOMOLOGY 

sparse hairs. The abdomen is rather long, the tracheal tubes are broad, 
band-shaped. The air-tube is stout, short, strongly tapered on outer 
half, over twice as long as wide, with the pecten running nearly halfway, 
followed by a single tuft of a few hairs. Each single pecten-tooth is a 
rather long spine with two large and some small teeth within and small 
ones without. The lateral comb of the eighth segment is composed of 
ten scales in a single row. The anal segment is short, wider than long, 
almost ringed by the plate, which nearly touches ventrally, but is not 
united. The ventral brush is moderate, directed posteriorly. The anal 
gills are long, wide, tracheate, with rounded tips. 

The larvae live in accumulations of water in artificial receptacles. 
Originally it was a tree-hole-inhabiting species, but is now wholly domesti- 
cated and is found in houses and in the vicinity of human habitations. 
The larvae thrive very well in water containing food refuse and in 
muddy water. 

Culex qumquefasciatus larva (see fig. 48) has the head rounded, 
widest through the eyes. The thorax is rounded, wider than long. The 
abdomen is moderate, with the anterior segments shorter. The tracheae 
are rather broad. The air tube is rather stout, tapered on outer half, 
four times as long as wide, with the pecten running about one-third, each 
pecten-tooth is broad with three to six branches. The lateral comb of 
the eighth segment is composed of many spines in a triangular patch. 
The anal segment is a little longer than wide, ringed by the plate. The 
ventral brush is well developed, confined to the barred area. The anal 
gills are rather short and broad, longer than the segment, tapered 
toward tips. 

The larvae are found most frequently in artificial receptacles, but 
also in ground pools in the vicinity of habitations when the water is 
sufficiently polluted. The species thrives best in water charged with 
animal matter and shows a preference for filthy water. Breeding goes on 
continuously while conditions are favorable. Under the most favorable 
conditions the larval period may be five or six days. 

Anopheles crucians larva has the head rounded, elongate, bulging at 
the sides, with the frontal portion before the antennas conically produced. 
The thorax is rounded quadrate, about as long as wide. The abdomen 
is stout, with the anterior segments shorter. The air tube is sessile, sub- 
quadrate, roundedly angled posteriorly. The lateral plates of the eighth 
segment are posteriorly armed with a series of about eight long, stout 
spines, separated from each other by from one to four short spines. The 
anal segment is about as long as wide, with a small dorsal plate. The 
ventral brush is well developed, of long branched tufts. The anal gills 
are moderate, about as the segment, slightly constricted centrally, blunt 
pointed. 



WHAT WE SHOULD KNOW ABOUT MOSQUITO BIOLOGY 271 

The larvae live in ground-pools, usually in tidal marshes. Breeding 
also occurs inland. Below New Orleans it is an abundant pest in the 
salt and brackish water marshes, where it occurs in undiminished numbers 
even in the winter. 

Anopheles pseudopunctipemiis larva differs but little from the pre- 
ceding but may be separated in the table which follows. 

This species is somewhat discriminating in choice of breeding place. 
It prefers as a rule water of great purity and rapidity of current. The 
larval food is by preference the soft green algae. It has been found, 
however, in irrigating ditches, in clear quiet pools formed by the over- 
flow of a watering trough, in ditches, pools and puddles, in tanks, well- 
holes and spring-holes full of algae. 

Anopheles punctipennis larvae (fig. 51) are found in all sorts of water 
in ground-pools and streams and occasionally in artificial receptacles. 
The larvae are found all the season, breeding being continuous until winter. 




Fig. 51. — Larva of the malaria mosquito, Anopheles punctipennis. (After Howard^ 

Dyar and Knab.) 

The larvae occur most commonly in swamps containing algae. Larvae 
have been found repeatedly in rain puddles, the water muddy and without 
trace of algal growths. 

Anopheles quadrimaculatus larva is most like that of punctipennis. 
The larvae occur in natural collections of water of a more or less per- 
manent nature. They often occur in the same locations as punctipennis 
but are more addicted to permanent stagnant water, such as the edges 
of sluggish rivers and marshes containing algae, less to springs and 
running water, and do not occur in temporary ground-pools filled by rains. 

The larvae of Anopheles are to be distinguished from Culex and Aedes 
by the habit of feeding. The two latter genera have larvae with long 
breathing tubes by which they hang from the surface of the water with 
the head downward, and feed on the life under the surface. Anopheles 
larvae have very short breathing tubes. They are surface feeders and 
are held to the surface by the tube and the fan-shaped abdominal tufts. 
The head is turned completely over with the mouth uppermost in the act 
of feeding. 



272 SANITARY ENTOMOLOGY 

The American disease-carrying Anopheles larvae may be partially 
separated by the following table: 

1. Abdomen with five pairs of fan-shaped tufts, the first pair small, 

punctipennis Say, quadrimaculatus Say. 
Abdomen with five pairs of fan-shaped tufts, 2. 

2. First and last pair of fan-shaped tufts smaller than the others, 

crucians Wiedemann. 

Fan-shaped tufts all. equal, each element in the tuft with long, 

slender apical portion, pseudo punctipennis Theobald. 






Fig. 52 (left).— Pupa of Culex. Greatly enlarged. (Howard.) From U. S. Dept. 
Agr. Farmers' Bull. 155, fig. 8. 

Fig. 53 (center). — Pupa of Anopheles quadrimaculatus. Greatly enlarged. (Howard.) 
From U. S. Dept. Agr. Office Secy., Circ. 61, fig. 12. 

Fig. 54 (right). — Pupa of Aedes argenteus, the yellow fever mosquito. Greatly en- 
larged. (After Howard, Dyar, and Knab.) 



THE PUPJ; 

Unlike other insect pupas, the mosquito pupae are active and capable 
of moving rapidly through the water. They depend upon communication 
with the air for respiration. The respiration takes place through a pair 
of appendages on the thorax, called the respiratory trumpets. By lash- 
ing the pair of chitinous plates at the apex of the eight segment, called 
paddles, the pupa can descend rapidly. It rises to the surface as soon 
as it ceases its efforts. The mosquito pupa is also peculiar in that it 
possesses eyes, which enable it to see the approach of an enemy and make 
its escape. Figures of the three genera discussed in the paper are given 
(figs. 52-54). 

ADULT MOSQUITOES 

The adult mosquitoes are known to all of us. The males take only 
vegetable food, but the females also require a blood feed, in many species, 
before they can oviposit. Various species attack insects, frogs, birds, 
and all types of mammals for their blood feed. Culex quinquefasciatus 
feeds at night, Aedes argenteus in the day time, and the Anopheles during 
the twilight hours of early morning and evening. 



WHAT WE SHOULD KNOW ABOUT MOSQUITO BIOLOGY 273 



Table of Adult American Disease-Carrying Mosquitoes 

1. Palpus of female as long as the beak (see fig. 55b) and the wings 
brown with yellowish-white spots or markings, (Anopheles), 3. 
Palpus of female shorter than beak (see fig. 55a) and wings with- 
out definite spots or markings, (Aedes, Culex), 2, 





Fig. 55. — Types of mosquito mouthparts: a, Short palpus form; b, Long palpus form. 
(Greene.) A = antenna, B = beak, P = palpus. 

£. A dark brown species with two curved, silvery white lines (resem- 
bling an inverted lyre) on top of body. Yellow fever mosquito 
(fig. 57), Aedes argenteus* 




Fig. 56 (left. — Adult Culex sollicitans. Much enlarged. (Howard.) From U. S. Dept. 

Agr. Farmers' Bull. 155, fig. la. 

Fig. 57 (right). — The yellow fever mosquito, Aedes argenteus: adult female. Much 

enlarged. (Howard.) From U. S. Dept. Agr. Office of Secy., circ. 61, fig. 13. 



3. 



Pale reddish-brown species with top of abdomen much darker and 
with five yellowish-white bands across the top (for a Culex 
see fig. 56), Culex quinquefasciatus. 

A dark brown species with a vein near the base of the wing 
yellowish-white and this vein having three distinct dark spots, 

Anopheles crucians. 



274 SANITARY ENTOMOLOGY 

A dark brown species with the wings mostly brown having a 
large, yellowish-white spot on the front edge of wing towards 
the tip, and a smaller light spot close to the tip. Fringe at 
the tip of wing dark, Anopheles punctipenms. 

A species very slightly smaller. Wings clear except along front 
edge where there are three large, yellowish-white spots towards 
the tip. The third spot is at the tip and the fringe at the tip of 
the wing is yellowish-white, Anopheles pseudopunctipennis. 

A brown species with the wings without pale, conspicuous mark- 
ings. Wings with four dark-gray to black spots on outer half 
(fig. 58), Anopheles qwadrimacidatws. 




Fig. 58. — A malarial mosquito, Anopheles quadrimaculatus Male at left and female 
at right. Greatly enlarged. (Howard.) From U. S. Dept. Agr., Office of Secy., 
Circ. 61, fig. 8. 

The yellow fever mosquito is more definitely marked than any other 
species of mosquito known. The general color is a dark-brown. On top 
of the thorax or back there are two silvery-white, curved lines which 
resemble an inverted lyre. 

REFERENCES 

Howard, L. O., Dyar, H. G., and Knab, F., 1912-1917.— The mosquitoes 
of North and Central America and the West Indies, 4 vols. This very 
fine monograph is the largest and most complete on this subject. 

Dyar, H. G., and Knab, F., 1917. — The genus Culex in the United States. 
Insecutor Inscitiae Menstruus. Vol. 5, Nos. 10-12. 



CHAPTER XIX 

Mosquito Control * 
W. Dwight Pierce 

Probably more money and more concentrated effort has been devoted 
to mosquito control throughout the world than to the control of any 
other disease-bearing insects. The anti-mosquito work now under way in 
the United States, under direction of the Public Health Service, is the 
biggest sanitary undertaking this country ever has gone into. When we 
consider the vast efforts of India, Italy, Panama, Cuba, and other coun- 
tries against these insects we realize the importance of the problem. 

PREVENTION OF MOSQUITO BREEDING 

By far the most important measures to be taken are those which pre- 
vent the breeding of mosquitoes, and therefore, we have to deal in some 
manner with water. If general mosquito control is sought, it is not essen- 
tial to ascertain the species breeding, but when large communities or 
armies are to be protected against disease-bearing mosquitoes, time may 
not permit of general mosquito control but may necessitate particular 
attention to the haunts of the disease bearers. 

Scouting 

The preliminary measures to be taken, therefore, are the organization 
and training of scouting parties designated primarily to search out the 
breeding haunts of these species, and report them to the details or squads 
designated for control work. The scouts must be trained entomologists 
skilled in the knowledge of mosquito haunts. They must examine the 
water in all receptacles in and around buildings, and in discarded vessels. 
They must seek out all puddles, hoof prints, wagon ruts, tree holes, 
ditches, and streams, and carefully examine these. A chart should be 
kept showing the location of all water and this can be marked in various 
ways to indicate the species present. Colored pin-markers on a wall 
chart are very serviceable. A field chart would have to be marked other- 
wise. 

1 This lecture was read September 30 and distributed October 7, 1918. It has been 
greatly revised. 

275 



276 SANITARY ENTOMOLOGY 

Determination of Source of Mosquitoes 

It is of primary importance in planning a mosquito campaign to 
determine the direction and distance of flight and behavior of mosquitoes 
in the area to be controlled. Zetek (1913, 1915) has elaborated methods 
for determining these points. He uses as dyes aqueous solutions of eosin, 
fuchsin, gentian-violet, bismarck-brown, methylene-blue, and orange-g, 
mixing one gram of dry stain to 50 c.c. of water. By means of an 
atomizer a fine spray is allowed to fall upon the mosquitoes. They should 
not be sprayed directly. Evening hours are best for their release and 
care must be taken not to carry away individuals on the body of the 
agent. There should be careful observations of wind, climatic condition, 
direction of flight of the mosquitoes, and the movement of human beings. 
To determine the flight window traps, examination of buildings and 
general sweeping are necessary. The place and hour of collection must 
always be noted. To detect the dye a testing solution is made of three 
parts glycerin, three parts alcohol, and one part chloroform and the 
specimens are individually touched with a camel's-hair brush moistened 
therein. 

Leveling and Filling Water Holes 

Details of men may be designated to look after the leveling of ground 
where water is apt to gather and remain, and to fill up small puddles, 
pools, hoof marks, ruts, etc., which serve no useful purpose and where 
drainage is inadvisable. Holes in trees should be filled up with cement. 
Stumps which hold water should be grubbed out and the stump holes 
filled. In rocky streams pot-holes in the rocks often breed many mos- 
quitoes. If possible the rock should be grooved, or removed, or the 
holes may be filled with cement. 

Ditching and Clearing Streams and Swamps 

Other details may be designated to clear stream beds and drain low 
lands. Spring lands, bogs, and swamps furnish an abundance of mos- 
quitoes and are the first places to receive the attention of the ditching 
squads. Ditches must be constructed to carry off standing water. These 
should be laid out by an engineer. The ditches must have straight banks 
and even bed and must be kept free of vegetation. Sometimes it is neces- 
sary to spray the vegetation along the ditches with oil, and burn. All 
borrow-pits and puddles caused by grading roads and railways should 
be connected up by a ditching system or filled. Flowing streams usually 
have trees along their sides. Under such trees water is often trapped 
and forms a quiet, undisturbed place for mosquito larvae. Trees must not 



MOSQUITO CONTROL 277 

grow on the edge of the bank. Tree roots must be removed from the 
stream. Any kind of vegetation growing in the bed of a stream favors 
mosquito breeding as it affords some protection against natural enemies, 
and prevents adequate artificial control. The stream bed must be clear 
of vegetation. The banks must be straightened and without overhanging 
ledges. There should be no obstruction to the free flow of the stream. 
If it meanders, a new and straight course ought to be constructed and 
the old course filled. Springs which furnish good water should be boxed 
and protected. Le Prince and Orenstein very ably describe in their 
book the method of clearing streams and propagation areas in jungles 
in the tropics. 

Clearing of Weed-Filled Bays and Lakes 

Large bodies of water in which dense growths of grass and weeds 
occur furnish great problems in many localities, and in tropical coun- 
tries especially, where feasible, it is often desirable to furnish the mos- 
quito squad with two motor boats and submarine saws or other imple- 
ments for cutting and removing vegetation. If this cut vegetation remains 
it aggravates the situation. Large lily leaves, which when alive furnish 
no place for breeding, will often, when dry, form cups for water in 
which mosquitoes breed prolifically. 

Drainage 

The construction of drainage systems should be done preferably by a 
sanitary engineer who understands the mosquito phases of the problem. 
The main ditches should be constructed first and later the laterals added. 
Sometimes where weed growth is rapid it is desirable to have a double 
parallel series of ditches, one only operating at a time except during heavy 
rains, with the idea that the idle ditch can be cleaned and shaped up. 
It is essential that the floor level of the ditch affords no opportunities 
for puddles to form after the greater part of the water has passed off. 
In permanent ditching it is sometimes feasible and advisable to line the 
ditch with concrete or at least to line the bottom. Weep-holes should be 
made at sufficient intervals to carry into the drain water which gathers 
on the outside of it. Branch ditches should enter the main ditch at an 
acute angle or on a curve. At the junction of ditches there should be a 
splash wall to confine the water within the ditch. Pot-holes formed in 
dirt ditches should be filled up after rains with gravel or stone and tamped 
hard (see Le Prince and Orenstein, pp. 137-14-4). 

In certain soils where seepage water outcrops abundantly on hill- 
sides, it is sometimes practicable to install an intercepting tile drainage 



278 SANITARY ENTOMOLOGY 

system. The tiles are laid at right angles to the flow of the seepage 
at the highest seepage water level, with a space of one-eighth to a quarter 
inch between joints. The grade of the trench bottom must be true. 
Tiles must not be located on soft mud where they may sink. The outlet 
should be well above the ground surface (see Le Prince and Orenstein,, 
pp. 130-136). 

Dr. C. W. Metz (1919) has set down certain very valuable principles 
in drainage, and describes the methods of surface and vertical drainage 
used by the Public Health Service. The treatment depends upon the 
sources of the water. The methods described above will suffice for rain 
water. For seepage water where tile drainage is not to be used the 
ditches must be dug at right angles to the flow of the seepage water, that 
is, across the exposed end of the water table. These ditches may be con- 
nected to main ditches which will carry the flow down the hillside parallel 
to the seepage flow. If the water table is too deep to be intercepted by 
one ditch, it may be necessary to dig additional intercepting laterals at 
intervals lower down. A swiftly running ditch is better than a sluggish 
one. Water, confined in a narrow channel will run more swiftly, give less 
surface, and be easier to oil, hence V-shaped ditches are usually pref- 
erable to wide-bottomed ones. The shape of the ditch will largely depend 
upon the nature of the soil. Where wide ditches are apt to form puddles 
in dry season, a small V-shaped ditch the width of a shovel may be made 
down the middle of the large ditch. 

Vertical drainage consists of sinking wells to conduct the water 
through relatively impervious soil into water-bearing sand or gravel. 
Such drainage is advisable only where surface drainage is difficult or 
expensive. In case the underlying stratum is deep down, holes should 
be bored and drain heads installed. The drain head will consist of a 
culvert-like box at the level of the bottom of the lake or pond which will 
conduct the water to the well. The receiving end will be screened to keep 
out debris with a coarse screen and a fine screen. The other end of the 
culvert is closed. Over the well will be a hole about one-fourth or one- 
third the diameter of the well, and this likewise will be covered with a 
screen. A pipe or funnel from the hole in the culvert into the well will 
reduce washing and crumbling of the sides of the hole. Soft soils will 
require that the well be cased with tile or iron pipe. 

Any one engaged in marsh drainage should familiarize himself with 
the methods in vogue in the great salt marsh drainage work of the State 
of New Jersey (Headlee, 1915). 

When ditches become matted with algae and other matter and contain 
mosquito larva, in some localities it is possible to construct water gates 
to permit temporary impounding of water, which will enable the ditch 



MOSQUITO CONTROL 279 

squads to thoroughly flush the ditch below the gate and remove all 
mosquito larva and algae. 

Larvicides 

The ditching, draining, and clearing of waterways insure a regular 
flow, carry off* all surplus water, and reduce but do not prevent mosquito 
breeding. It is necessary to use some additional means of control and 
for this purpose various larvicides have been applied, but principally 
kerosene, crude oils of paraffin and asphaltum base, as well as 
creosote oils. 

The question of the effect of oils on mosquito larvae is most thor- 
oughly discussed by Freeborn and Atsatt, who find that the toxicity of 
the petroleum oils as mosquito larvicides increases with an increase in 
volatility, the more volatile oils producing the more marked lethal 
effects. The volatile constituents of the oils contain the principles 
that produce the primary lethal effects. The lethal effects are produced 
by the penetration of the tracheal tissue by the volatile gases of the oils. 
In the heaviest and least volatile oils having a boiling point greater than 
250° F., this action may be supplementary or apparently secondary to 
the effect of actual contact of the oil with the body tissue, or perhaps 
to mechanical means such as suffocation or plugging of the tracheae. 
They found that oils which killed very quickly did so by means of the 
volatile gases, whereas in the case of oils with slow effectiveness the 
mechanical suffocation may be the cause of death. 

This paper is so recent that it has not been possible to obtain a 
mass of evidence on the practical effectiveness of different grades of oils 
used as larvicides. Kerosene and crude oil are the oils most commonly 
used in general practice. Le Prince and Orenstein prefer crude oil to 
kerosene because of the film made by kerosene, its greater expense, inflam- 
mability, and liability to be wasted because of its transparency. 

These authors have set down a number of requirements for a good 
larvicide : 

1. It shall have a high toxic power, so that a small quantity may 
suffice for a large volume of water. 

2. It shall kill rapidly in order that subsequent dilution and weaken- 
ing by rain have as little effect as possible. 

3. It must be uniform in its toxic power and capable of standard- 
ization. 

4. It should mix freely with brackish and alkaline waters. 

5. It must be harmless to man and domestic animals, when in the 
dilution necessary for larvicidal action. 

6. It shall not be susceptible to rapid deterioration. 

7. It must be inexpensive. 



280 SANITARY ENTOMOLOGY 

They did not find any substance which fulfilled all these conditions, 
but found a soap (now known as the Panama larvicide) to meet most of 
their requirements. This was made of the following ingredients : 

Resin 150 to 200 pounds 

Soda (caustic) 30 " 

Carbolic acid (sp. gr. 0.97) 150 gallons 

This makes a liquid soap which freely emulsifies with fresh water. 
The carbolic acid must have at least 15 per cent of phenols and no 
greater specific gravity than 0.97. 

This larvicide is manufactured as follows : Heat the carbolic acid 
in a steel tank with steam coil. When steaming hot add the resin and 
continuously stir the mixture by means of a paddle agitator until com- 
plete solution is effected. Dissolve the caustic soda in 6 gallons of water 
and add to the mixture. Heat and stir for five minutes. Draw a sample 
and pour into water. If it emulsifies the process is complete, and the 
product may be put into shipping drums which must be tightly closed. 

Oiling 

There are many ways of applying the oil. The most common method 
is by knapsack sprayer or, where the ditch is along the road, by horse- 
drawn tanks fitted with a spraying bar. For slow-moving water and 
stagnant water, as well as the treatment of ruts, puddles, hoof prints, 
and so forth, these methods are satisfactory. Dr. Metz found that 
he got excellent results in boggy lands especially by applying a thin 
mist of commercial creosote. A very small quantity will kill mosquito 
larvae. 

For moving water there are many devices for maintaining a regular 
dripping of oil from a suspended vessel upon the surface of the water. 
Such devices can easily be rigged up by any pr-actical man. Dr. M. J. 
White of the Public Health Service modified this method by conducting 
the oil to the water by means of a wick (Metz 1919). 

The war has brought about the new and even more efficient methods 
of oiling which have been developed along many angles by Dr. W. L. 
Mann, the Post Surgeon, and Lieut. E. C. Ebert of the Marine Corps at 
Quantico, Va., with the assistance of Pharmacist's Mate Carl Duncan. 
They have found that sawdust impregnated with crude oil will hold it for 
a long time and will slowly give it up to the water. They therefore place 
the sawdust impregnated with oil in a box and sink it in a flowing* stream 
(fig. 60) ; or they throw a few grains of sawdust in a hoof print, or a 
handful on a puddle; or they fix a floating boom to hold back of it a 



MOSQUITO CONTROL 



281 



quantity of sawdust and give off a constant film. Thus for each condi- 
tion, with a slight modification of the application, they obtain an excel- 
lent and lasting film not destro} r ed by rains. Dr. Metz modified this 
method by putting the oil-soaked sawdust in bags which he fastened to 
the bottom of streams. Probably no other system of oiling is as adaptable 
or as satisfactory as this sawdust method. Geiger and Purdy (1919) 



eUoJfW 




Fig. 59. — Submersible automatic bubbler for distributing oil over surface of water. 

(Ebert) 



have just reported success in reduction of mosquito incidence in rice 
fields by broadcasting oil-impregnated sawdust and without injury to 
the rice. 

Dr. Ebert, early in 1918, developed an automatic oiler (fig. 59) con- 
sisting of a cylinder sunk beneath the water which takes in water and 




Fig. 60. — Method of petrolization with oil soaked sawdust. (Ebert.) 

displaces the oil, the amount of displacement being regulated by spigots. 
This oiler dropped under a bridge in a big river or placed in a large 
tidal bay amidst rank vegetation produces a constantly, evenly dis- 
tributed film of oil which is very effective. The size of the cylinder is 
gauged by the size of the stream. The distance to be placed apart must 
depend upon the film obtained. Lieut. Brigham (1918) of the Army 
Medical Corps used the same principle when he filled a bottle with crude 
oil, cut two grooves in the cork and poured oil in one groove. When 
dropped in the water this automatically bubbled. To reach inaccessible 



282 SANITARY ENTOMOLOGY 

pools he fitted a parachute to the bottle and shot it with a bow gun, 
using rubber bands for power. 

Artificial Containers of Mosquito Larvce 

In mosquito work much attention must be given to all types of 
artificial water containers, as rain barrels, cisterns, latrines, tin can 
dumps, garbage cans, gutters, water pitchers, flower vases, aquaria, 
table isolation receptacles in tropical countries, cesspools, sewers, toilets 
and flushing boxes, traps in sinks, drinking fountains, water troughs, 
etc. Flushing, periodic emptying, covering with oil film, stocking with 
fish, are among the possible expedients available in one or another of 
the cases. Capt. D. L. Van Dine and Dr. W. V. King have devised a new 
treatment for water in fire barrels and water tanks for storage of 
water to be used in cleansing cans, in each of which cases oil is very 
undesirable. These receptacles may be treated with borax at the rate 
of % pound to 10 gallons of water; or with 1 pound of salt to 10 gallons 
of water. 

Fish as Mosquito Control 

Among the principal natural enemies of mosquitoes are fish and in 
permanent ponds and lakes and streams, the stocking with the proper 
species of fish may be considered as one of the most satisfactory methods 
of mosquito control. In this country top minnows and goldfish are 
commonly used for this purpose. The Bureau of Fisheries lists the fol- 
lowing fresh water fish available for introduction in American waters 
infested by mosquitoes : The killifishes, Fundulus diaphanus, F. dispar, F. 
notatus, F. chrysotus, and F . nottii; the top minnow, Gambusia affinis; 
Heterandria formosa, Mollienisia latipinna, Enneacantlius obesus, E. 
gloriosus, Mesogoniatius chaetodon, Centrarchus macropterus, Lepomis 
cyanellus, L. gibbosus, Elassoma zonatum, Notemigonus crysoleucas, 
Labidesthes sicculus, and Carassius auratus (goldfish). (Radcliffe 1915.) 

For use in salt water or brackish water the following fishes are avail- 
able: Fundulus majalis, F. heterocliteus, F. similis, Lucania parva, L. 
venusta, and Cyprinodon variegatus. (Radcliffe.) 

The most complete summary of the species of fish available in various 
parts of the world is given by Hegh (pp. 140-150). Howard, Dyar and 
Knab and also Le Prince and Orenstein discuss the subject. The methods 
used in distributing fish in various types of water in India are described 
by Wilson (1917). 

In this country any one desiring to stock a reservoir or other body 
of water with fish should immediately communicate with the Bureau of 
Fisheries at Washington. 

The Panama larvicide and creosote are toxic to fishes, and 



MOSQUITO CONTROL 283 

undoubtedly some of the volatile oils are also, although the literature 
speaks only in general terms on this subject' 

Destruction of Adult Mosquitoes 

Howard, Dyar and Knab, and also Hegh, cite various methods of 
destruction of adult mosquitoes in dwellings, such as puffing powdered 
pyrethrum into nooks frequented by mosquitoes, fumigation by burning 
pyrethrum, sulphur or cyanide fumigation, vapors of cresyl and of creo- 
line. Le Prince and Orenstein describe a labyrinth trap for windows, 
quite similar to the Hodge window fly trap. Hegh figures and describes 
other fly traps. 

PROTECTION FROM MOSQUITOES 

Protection of Dwellings from Mosquitoes 

In mosquito sections the screening of all habitations against mos- 
quitoes is essential. This must be done thoroughly and the screens must 
be carefully examined and repaired. When holes or openings occur in 
the screening, the mosquitoes enter and are trapped and the building is 
often worse off than if unscreened. 

For protection against Anopheles alone, a 16-mesh wire screen is 
sufficient, but small Aedes can pass through this and therefore 17 or 
18-mesh is necessary. Le Prince and Orenstein give the specifications for 
the 18-mesh screen to be of 90 per cent pure copper and not more than 
one-half of one per cent of iron for damp tropical countries, the gauze 
having eighteen strands of wire of one one-hundredth of an inch diameter 
in each linear inch. The best type of screen for salt or acid air will 
probably be a screen coated with an acid proof, noncorrosive alloy such 
as Gageite. In many parts of the United States other types of wire 
screening are thoroughly efficient. 2 

Where mosquitoes are abundant the double door vestibule arranged 
so that the two doors can not be opened at the same time is highly 
desirable when practicable. In tropical countries with verandas around 
the entire house, the entire screening of the verandas is essential. Lieut. 
Brigham (1918) describes an ingenious mosquito electrocuter. 

Protection of the Individual 

Campers are in the habit of using almost anything that will make a 
dense smudge to drive away mosquitoes. The fumes of burning pyrethrum 

3 Mr. F. C. Bishop has for several years been making tests of serviceability of many 
types of screening in various parts of the country, and although he has not submitted 
a final report, will gladly advise any one desiring this information for official purposes. 
His address is Box 208, Dallas, Texas. 



284 SANITARY ENTOMOLOGY 

powder are not obnoxious to most persons and are very effective in freeing 
a room of mosquitoes. The powder slightly moistened and moulded into 
a candle will burn slowly like punk. The essential oil of the powder may 
be volatilized by placing on a metal screen above a lamp chimney. The 
odor is only slightly perceptible and not unpleasant. 

For protection of the body, camphor, oil of citronella, oil of cassia, 
and other essential oils are found efficacious. Howard, Dyar, and Knab 
recommend as the best in their experience: 



Oil of citronella 


1 oz. 


Spirits of camphor 


1 oz. 


Oil of cedar 


V2 oz. 



This may be rubbed on the clothes or body. A few drops on a bath 
towel hung over the bed will keep Culeoo pipiens away for a whole night. 
Graybill lists many repellents against flies which have been tried on 
animals. The most successful substances tried by him were 50 per cent 
pine tar in cotton seed oil, or 10 per cent oil of tar in cotton seed oil, 
when applied lightly. Fish oil is a very effective repellent. Bishopp's 
fish oil repellent is very effective in keeping flies from livestock when 
applied lightly. It consists of : 



Fish oil 


1 gallon 


Oil of tar 


% ounces 


Oil of pennyroyal 


£ ounces 


Kerosene 


Y 2 pint 






Mosquito nets for the bed are used in many parts of the South where 
the buildings are unscreened. Campers who sleep in hammocks may 
easily arrange a good sleeping net by tying a rope to the hammock sup- 
ports and hanging from this a tent-shaped net which can be fastened at 
the ends and tucked in beneath the blankets. 

Hegh illustrates mosquito bars for tent coverings, for tent doors, 
and soldiers' cots, and also a mosquito bar fastened inside a soldier's 
small field-tent so that the sides of the tent can be raised to give air. 
Various type of protective headgear have been described for troops in 4 
tropical countries, two of which are illustrated by Hegh. Simpson illus- 
trates a new headgear invented by his wife, which can be worn by day 
and at night. 

The references cited below are worthy of study in connection with 
this lecture. There are many other works in all languages on the 
special problems of different countries, most of which are listed by 
Howard, Dyar and Knab. 



MOSQUITO CONTROL 285 



BIBLIOGRAPHY 



Brigham, P. H., 1918. — An automatic oiling device. Mosquito electro- 
cuter. Military Surgeon, vol. 43, No. 2, pp. 224-226. 

Freeborn, Stanley B., and Atsatt, Rodney F., 1918.— The effects of 
petroleum oils on mosquito larvae. Journ. Econ. Ent., vol. 11, No. 3, 
pp. 299-307. 

Geiger, J. C, and Purdy, W. C, 1919. — Experimental mosquito control 
in rice fields. Journ. Amer. Med. Assoc, vol. 72, No. 11, pp. 774- 
779. 

Graybill, R. W., 1914. — Repellents for protecting animals from the 
attacks of flies. TJ. S. Dept. Agr. Bull. 131, 26 pp. 

Headlee, T. J., 1915. — The mosquitoes of New Jersey and their control. 
N. J. Agric. Expt. Sta., Bull. 276, pp. 10-135. Illustrates common 
mosquitoes. 

Hegh, E., 1918. — Comment nos Planteurs et nos Colons peuvent-ils se 
proteger contre les Moustiques qui transmettent des maladies. Min- 
ister of Colonies, Service of Agriculture of Belgium, Etudes de Biologic 
agricole, No. 4, 200 pp. 

Howard, L. O., Dyar, H. G., Knab, F., 1912.— The Mosquitoes of North 
and Central America and the West Indies. Carnegie Institution of 
Washington, vol. 1, pp. 320-449. 

Howard, L. O., 1911. — Remedies and Preventives against Mosquitoes. 
U. S. Dept. Agr., Farmers' Bull. 444. 

Le Prince, Joseph A., and Orenstein, A. G., 1916. — Mosquito Control in 
Panama, The Eradication of Malaria and Yellow Fever in Cuba and 
Panama. G. P. Putnam's Sons, 355 pp. 

Mann, W. L., and Ebert, E. C, 1918. — Some suggested improvements in 
methods of petrolization of mosquito breeding areas. Military Sur- 
geon, November 1918. 

Metz, C. W ., 1919. — Some aspects of malaria control through mosquito 
eradication. Public Health Reports, vol. 34, No. 5, January 31, 
pp. 167-183. 

Radcliffe, L., 1915. — Fishes destructive to the eggs and larva? of mos- 
quitoes. U. S. Department Commerce, Bur. Fisheries, econ. circ. 17, 
pp. 1-19. 

Simpson, W. J. R., 1919. — The sanitary aspects of warfare in South- 
eastern Europe. Journ. Trop. Med. and Hyg., vol. 22, No. 7, pp. 
58-66. 

Zetek, J., 1913. — Determining the flight of mosquitoes. Ann. Ent. Soc. 
Amer., vol. 6, No. 1, pp. 5-21. 

Zetek, J., 1915. — Behavior of Anopheles albimanus Wiede, and tarsi- 
maczdata, Goeldi. Ann. Ent. Soc. Amer., vol. 8, No. 3, pp. 221-271. 



CHAPTER XX 

Louse Borne Diseases * 
W. Dwight Pierce 

The parasitic lice belong to two closely related orders, the Anoplura 
or Siphunculata, commonly called sucking lice or vermin, and the Mal- 
lophaga, called biting lice, differing principally by the formation of the 
mouth parts. The sucking lice are parasitic principally on mammals, 
and the biting lice on birds, but some of the latter also attack mammals. 
They are more or less definitely limited according to their species to 
definite species or genera of animal hosts. All cause great annoyance and 
worry and probably by their attack frequently cause death of the host, 
especially young hosts. 

We are especially concerned with the sucking lice in this lecture, 
but will include a few notes on the biting lice. Some of the most serious 
diseases of man, especially when congested in crowded populations or in 
armies, are caused or carried by lice. Probably many fatalities among 
wild animals and birds are due to inoculable diseases carried by lice, which 
have never been investigated. 

I. DIRECT EFFECT OF LOUSE ATTACK 

The attack of lice on the body is in itself exceedingly annoying and 
leads to a great deal of itching and scratching. The attack by the 
various species of lice is differentiated by terms applicable to each. The 
attack by the body louse, Pediculus corporis DeGeer, or as it is known 
by Nuttall (1917), Pediculus humanus var. corporis, is known as pedic- 
ulosis corporis. The attack by the head louse, Pediculus humanus 
Linnaeus, commonly known as capitis DeGeer is called pediculosis 
capitis. Attack by the pubic louse, Phthirus pubis Linnaeus, is known 

as PHTHIRIASIS. 

1. Types of Pediculosis Corporis 

Nuttall (1917) has described a considerable number of recorded types 
of dermatitis caused by louse attack. 

1 A lecture on this subject was delivered June 3, 1918, and distributed in mimeo- 
graphed form, but on account of the great change in the subject since then, the present 
lecture is practically rewritten. 

286 



LOUSE BORNE DISEASES 287 

URTICARIA. — The attack of the body louse, popularly called 
"cootie," produces minute haemorrhagic spots which are accompanied by 
more or less urticaria, the itching leading to scratching. The bites are 
principally distributed over the neck, back and abdomen. Peacock found 
louse rash distressingly common among the British troops. 

MELANODERMIA. — In tramps, chronic drunkards, and vagabonds 
who have harbored lice for many years, the skin over the areas most fre- 
quently bitten becomes rough, hardened, and deeply pigmented, a condi- 
tion known as morbus errorum or vagabond's disease. This skin pigmen- 
tation, also called melanodermia, may extend to the mucous membranes, 
being visible in the mouth and is sometimes confused with Addison's 
disease (Nuttall 1917). 

ECZEMA. — Frequently the attack of the lice causes an eczematous 
inflammation of the skin, with exudation of lymph. 

PYODERMIA.— Nuttall records PUSTULAR DERMATITIS and 
PRURIGO SENILIS due to louse bite. Smith (1918) considers the 
pyodermia (ecthyma, etc.) caused by the body louse a more serious dis- 
abling skin disease than scabies. Various authors have claimed that 
the lice sometimes burrow under the epidermis forming so-called "covered 
louse-ulcers," which on opening liberate many lice. 

TOXEMIA. — Moore cites instances of intoxication of the system 
from louse injected toxins. 

#. Types of Pediculosis Capitis 

Head lice may produce urticaria, eczema and pyodermia, of which the 
most important type is mentioned in the next paragraph. Pinkus states 
that the inflammation of the scalp may lead to falling out of the hair. 

PLICA POLONICA. — As results of eczema or pustular dermatitis of 
the scalp the exudations of the skin lead to formation of scabs and 
crusts in the hair especially at the nape of the neck, and this condition 
has been called plica polonica because it is so frequently observed among 
the poor Jewish population of Poland. (Nuttall 1917.) 

3. Types of Phthiriasis 

The pubic nee occur in the pubic regions principally, but are also 
found in the axillae, eyebrows, and other parts of the body. They 
cause great discomfort unless the host is hardened to them. (Nuttall 
1918.) 

PRURITUS. — The attack of this louse causes a pruritus which can 
be violent and leads to much scratching day and night. It is thought that 
the itching is primarily caused by the toxic saliva of the louse. 



288 SANITARY ENTOMOLOGY 

PYODERMIA. — Crab louse attack may result in papular eruptions 
complicated by eczematous inflammation. 

BLEPHARITIS.— Dubreuilh and Beille state that when the lice are 
abundant on the upper eyelids they may cause blepharitis of the ciliary 
borders of the lids with a variable amount of pruritus. 

TOXEMIA. — Payne attributes fevers and headaches to toxic action 
of Phthirus. Nuttall has also recorded a rise in bodily temperature due 
to the attack. 

MACULAE COERULEAE.— The occurrence of this louse upon the 
body is usually indicated by the presence of bluish spots on the skin due 
either to a genuine pigmentation according to Oppenheim or a toxic 
erythema according to Huguenay. Nuttall (1918) gives quite a dis- 
cussion of the subject. 

MELANODERMIA.— Nuttall (1918) states that this louse may also 
cause a discoloration of the skin amounting almost to blackness and 
involving the mucous membranes and nails. 

J^. Effects of Attack of Other Lice 

Railliet has seen Haematopinus form real subepidermal nests in an 
old horse. 

Imes states that biting cattle lice, Trichodectes scalaris often form 
colonies around the base of the tail, over the withers, and on other parts 
of the animal, and produce lesions resembling those of scab. These 
lesions vary in size from one to five inches in diameter. The skin over 
these areas appears to be raised and ringworm may be suspected, but 
when the lesion is manipulated the scarf skin falls off, exposing the lice 
grouped on the raw tissues beneath. Under such conditions the irrita- 
tion may be fully equal to that caused by scab. 

The sucking cattle lice, Haematopinus eurysternus and Linognathus 
vituli, act as a contributing cause to increase the death rate among 
poorly nourished cattle of low vitality. Even mature cattle of full vigor 
when very lousy will not gain weight and there is a loss in the production 
of meat and milk. 

Chickens, turkeys, pigeons, and all other poultry as well as wild birds, 
are abundantly parasitized by biting lice and are seriously injured by 
the attack. The first symptoms of lice infestation usually are droopi- 
ness, lowered wings and ruffled feathers. Diarrhea follows and the 
chickens often die in a few days. Older fowls may not show ill effects 
other than decrease in egg production. 



LOUSE BORNE DISEASES 289 

II. TRANSMISSION OF DISEASES BY LICE 

1. Diseases of Plant Origin 

Thallophyta: Fungi: Ascomycetes: Gymnoasceae 

Achorion schoenleini (Lebert 1845), the cause of FAVUS, or POR- 
RIGO, a fungus disease of the hair follicles, may be spread by head lice 
according to Aubert (1879). 

Thallophyta: Fungi: Hyphomycetes 

Malassezia species, causing the scaly skin diseases called PITY- 
RIASIS, are claimed to be spread by lice by Aubert (1879). 

Thallophyta: Fungi: Schizomycetes: Coccaceae 

Staphylococcus pyogenes aureus and albus, the cause of IMPETIGO 
CONTAGIOSA, an acute contagious pustular inflammation of the skin 
can be carried by head lice, as was proven by Dewevre (1892) by remov- 
ing lice from impetigo cases and placing them on the heads of healthy 
children, who some days later developed the disease. This claim has 
been supported by various authors. Widmann (1915) attempted to 
transmit Staphylococcus septicaemia by louse bite and failed although he 
recovered living cocci from the louse feces after 60 hours but not later. 
In view of recent findings with other louse-borne diseases, we may expect 
that infection could have been obtained by slightly abrading the surface 
on which the lice had defecated. 

Diplococcus intracellularis meningitidis Weichselbaum. Pizzini 
(1917) found a strong parallel in two Italian outbreaks of CEREBRO- 
SPINAL MENINGITIS with the occurrence of lice on soldiers and civil- 
ians who contracted the disease. Some patients were found to have in 
their underclothing louse vectors of the Meningococcus, or they were 
found to have handled garments infested with such lice. The months 
during which the disease is prevalent are those during which lice are 
definitely parasitic. 

Diplococcus pemphigi contagiosi Manson, the cause of TROPICAL 
IMPETIGO, is said by MacGregor (1917) to be carried by lice. 

Pneumococcus. — In experiments conducted by Widmann (1915), he 
succeeded in making lice bite mice in which he had produced Pneumococcus 
septicaemia. He could not infect other mice by means of the louse bites 
but found the louse feces infective during the first 24 hours. The cocci 
were confined to the intestinal tract and did not multiply therein. 



290 SANITARY ENTOMOLOGY 

Conjunctivitis. — DeFont Reaulx (1912) and other writers regard 
head lice as the cause of PHLYCTENULAR CONJUNCTIVITIS, and 
Hudson (1914) states that its sequela PHLYCTENULAR KERATITIS 
prevails among Board School children in England, causing much suffer- 
ing and corneal scars with resultant disabilities. He refers severer cases 
primarily to head lice, infective material being carried from the scalp to 
the eyes by the hands. 

Other Septicaemias. — Sobel in 1913 as a result of eleven years' 
experience with New York school children states that head lice are the 
indirect cause of pyogenic infection, frequently leading to involvement 
of the lymphatic glands followed by suppuration, and that lice also 
indirectly cause IMPETIGO CONTAGIOSA, DERMATITIS, FURUN- 
CULOSIS, ECZEMA AND FOLLICULITIS. Pinkus in 1915 describes 
similar results and states that the inflammation of the scalp may lead to 
the falling out of the hair. 

Thallophyta: Fungi: Schizomycetes: Bacteriaceae 

Bacillus pestis Kitasato, the cause of PLAGUE, is referred to by 
various authors. Swellengrebel and Otten (1914) experimenting with 
clothes lice from plague patients in Dutch East India, and DeRaadt 
(1916) have succeeded in causing death by plague in experimental ani- 
mals by subcutaneous inoculations of crushed lice. Herzog in Manila 
found Bacillus pestis in three head lice from a child dead of plague 
(Bulloch and Douglas, 1909). There is no evidence that plague can be 
carried by the bite of lice. 

Bacillus typhosus Eberth. — In like manner Abe (1907) claims to 
have recovered Bacillus typhosus from body and head lice fed on 
TYPHOID FEVER patients in 75 per cent of the insects examined. 

Bacillus leprae Hanson. — McCoy and Clegg (1912) have likewise 
found Bacillus leprae in two head lice out of many examined from patients 
suffering with LEPROSY. 

Summ\ary of Plant-Caused Diseases 

All of the various cases cited above are probably to be considered 
purely as examples of mechanical transmission by scratching of the feces 
of the lice containing the organism into the skin. The organisms of 
impetigo contagiosa, tropical impetigo, favus, pityriasis, Pneumococcus 
and Streptococcus septicaemias, phlyctenular conjunctivitis and keratitis, 
plague, typhoid fever, leprosy, and meningitis are all bacteria or fungi. 
It is to be hoped that experiments in inoculation of feces will be carried 
out with those organisms in which the exact role of the louse is still unde- 



LOUSE BORNE DISEASES 291 

termined. The almost irresistible desire to scratch a louse bite should 
make louse transmission of any organism taken up from the blood, which 
can successfully pass through the lice in their feces, a very easy matter. 
In case of typhoid fever, if there is transmission it might be through soil- 
ing fingers on crushed lice. This consideration leads me to suggest that 
some one take up the question of louse transmission of gonorrhoea, 
syphilis, smallpox, and other diseases, giving special attention to inocu- 
lation of infected feces. 



%. Diseases of Unknown or Uncertain Origin 

BERI-BERI. — Manson (1909) has advanced the hypothesis that lice 
may possibly transmit beri-beri or polyneuritis, a disease whose cause is 
undetermined. Bradford, Bashford, and Wilson (1919) have found a 
filterable virus in acute infective polyneuritis. Daniels conducted an 
unsuccessful attempt in transmitting beri-beri from man to an orang- 
outang by means of lice, due probably to the inability of the lice to live 
on the host. (Castellani and Chalmers, p. 1216.) He did not attempt 
inoculation of the feces, apparently expecting to convey the disease by the 
louse bite. The majority of writers treat beri-beri as a nutritional dis- 
ease due to absence of vitamines. 

TYPHUS FEVER.— Acting on the suggestion of Sergent and Foley 
in Algeria, the transmission of typhus fever by the louse was first proven 
by Nicolle, Comte, and Conseil (1909) working in Tunis. They success- 
fully transmitted typhus from monkey to monkey by means of the bites of 
infected lice (Pediculus corporis) that had fed on a typhus fever patient 
1-7 days previously. A few months later Ricketts and Wilder (1910) 
working independently in Mexico reported successful infection of monkeys 
that were bitten by Pediculus corporis previously fed on typhus patients, 
and they also infected monkeys by placing the gut contents of such lice on 
scarified skin, three days after the lice had fed upon a typhus monkey. 
Shortly thereafter Ricketts succumbed to an attack of typhus. 

Further proofs of transmission of typhus fever by louse bites were 
published by Wilder (1911), Goldberger (1912), and Anderson and Gold- 
berger (1912); proofs of transmission by inoculation of crushed lice 
were published by Wilder (1911), Goldberger (1912), Prowazek (1913) 
and Nicolle, Blanc, and Conseil (1914). The last named authors proved 
that the feces of lice when inoculated were infective at least 6 days after 
the lice had fed on a typhus fever patient. 

Wilder (1911), Sergent, Foley, and Vialatte (1914) and Da Rocha- 
Lima (1916) claim that typhus fever is hereditarily transmitted by lice, 
but Anderson and Goldberger (1912) and Nicolle, Blanc, and Conseil 
(1914) hold that there is no proof of hereditary transmission. 



292 SANITARY ENTOMOLOGY 

No definite organism has been finally fixed on as the cause of typhus 
fever although several have been described. Plotz (1914) and others, 
with excellent reasons, regard Bacillus typhi exanthematici as the cause. 
Bodies called Rickettsia prowazeki Da Rocha-Lima (1916), are described 
by Da Rocha-Lima, Noeller (1916), and others, as the causative organ- 
ism, and it is claimed that they undergo multiplication in the cells of the 
midgut of infested lice. Whether Rickettsia is the cause of the disease or 
a product of the contagium is still uncertain. Stempell (1916) describes 
a Protozoan, Strickeria jiirgensi, which he suspects to be the cause of 
typhus, and claims that it undergoes part of its development in the in- 
testines of Pediculus corporis, and is sometimes transmitted to man in 
large numbers. Rabinowitch (1914-1916) regards Diplobacillus exanthe- 
maticus as the cause; Penfold (1916) describes a Micrococcus; Proescher 
(1915) describes minute Diplococci and Diplobacilli as present in the 
endothelial cells of the human subject. Finally Futaki (1917) has 
described Spiroschaudinma exanthematotyphi from the liver and urine of 
patients dying of typhus and has found the same organism in lice. Brumpt 
(1918) discusses Rickettsia prowazeki Da Rocha-Lima, the so-called 
cause of typhus fever, and claims that it is a coccobacillus and that he 
found it in 73.6 per cent of the lice {Pediculus corporis) from healthy 
prisoners in France. He found that these lice infected with this organism 
remained infective all their lives and therefore concludes that Rickettsia 
cannot be the cause of typhus fever, even though it may be transmitted by 
the lice to men and again taken up by them. In experiments on himself 
with infected lice he did not produce any infection. Brumpt perhaps 
found the Rickettsia pediculi which is associated with normal lice. 

TRENCH FEVER. — This disease has only recently been recognized, 
having passed even in the early days of the war under the initials P. U. O., 
or pyrexia of unknown origin. Many of the greatest investigators in the 
various armies concentrated attention on this baffling disease of the 
trenches which stood among the highest of the disabling diseases of the 
Western front. The first records of the connection of the louse were 
contained in statements of Davies and Weldon (1917, 1918) that one of 
them had produced the disease in himself by permitting infected lice 
(Pediculus corporis) to bite him. The incubation period was 12 days. 
Early in 1918 two separate committees, the British under Sir David 
Bruce and Major W. By am, and the American under Dr. R. P. Strong, 
succeeded in proving louse transmission. The English committee (Bruce 
1918) in an experiment in which lice were crushed on a scarified area 
of skin of volunteer patients incubated the disease in eight and ten days. 
In experiments with the feces of lice fed on trench fever patients, a small 
amount of dried excreta rubbed on a scarified area of skin, incubated the 
disease in three men on the sixth, seventh and eighth days. Blood from 



LOUSE BORNE DISEASES 293 

one of these men on the second day of fever inoculated in another volunteer 
produced a typical attack after an incubation period of five days. As the 
lice will usualty leave a man with fever and migrate to a man with normal 
temperature, it is easy to see how the disease is propagated. 

The British Trench Fever Committee's reports presented by Major 
Bvam and others (1918) summarize the findings of the committee under 
18 paragraphs. They proved transmission of the fever by the feces of 
lice, that the disease is not native to the louse, and that it is not heredita- 
rily transmitted. The feces of the lice were only infective on the eighth 
to twelfth day after the lice had taken up the virus, proving a devel- 
opmental cycle in the lice. Transmission by the bite alone was not ob- 
tained. The incubation period after inoculation is at least eight days. 

On the other hand the American Trench Fever Committee (Opie 1918 ; 
Strong, etc., 1918) claims that the fever is transmitted by the bite of 
the lice from 19 to 25 days after the virus was taken up by the lice. 
This is probably the sum of the developmental period in the louse and the 
incubation period after inoculation. They claimed that the virus is not 
filterable, but is inoculable. The patients were allowed to scratch, and 
probably this was the way inoculation took place. It is quite possible, 
however, after lice have been confined on the skin for a time and have 
consequently covered the entire surface with their excreta, that they may 
inoculate the virus when they puncture the skin through this film of 
excreta. 

Arkwright, Bacot, and Duncan (1918) published a long series of 
studies with Rickettsia bodies which they think show a very possible 
connection with trench fever. Apparently these bodies occurred prin- 
cipally in lice capable of causing infection. The lice do not show these 
bodies in their feces nor do their feces become infective until five to ten 
or twelve days after feeding on infective blood. The majority of lice 
whose feces showed Rickettsia were infective and caused trench fever, 
while the majority which did not show Rickettsia were not infective. 
These same authors (1919) continued their studies with Rickettsia 
quintana, the bodies found associated with trench fever. Rickettsia is 
found in the lice on the fifth to twelfth days after feeding on a trench 
fever patient. Lice are infective on the fifth to twelfth days. Infected 
lice contain Rickettsia and their feces are high in the bodies. There is 
no hereditary transmission in lice. Whether Rickettsia is the cause or 
the product of the contagium is undetermined. 

L. Convy, and R. Dujarric de la Riviere (1918) described Spirochaeta 
gallic a as a probable cause of trench fever. 

The Haemogregarina gracilis Wenyon, suspected to be connected with 
the disease, has since been proven not to have any connection. 

Bradford, Bashford, and Wilson claim to have found a filterable virus 



294 SANITARY ENTOMOLOGY 

in trench fever, the organism measuring 0.3 jjl to 0.5 [x, and being anaero- 
bic. A similar organism was recovered from four separate supplies of 
infected louse excreta. 

VOLHYNIAN FEVER.— This obscure European fever also called the 
Hiss-Werner disease, is claimed by Topfer (1916) to be carried by lice. 
Jungmann and Kuczynski (1917) have confirmed this, claiming that an 
early diagnosis of Volhynian fever is possible by examination of the lice 
taken from patients. Da Rocha-Lima (1917) points out the similarity 
of this disease to typhus fever, and described Rickettsia pediculi which 
he believes is the causative organism, and which develops on the epithelial 
cells in the lumen of the stomach of the louse. Arkwright, Bacot and 
Duncan (1919) regard R. pediculi as normal to lice. Five-day fever, also 
called Febris qumtana, is identical with Volhynian fever. Werner and 
Benzler (1917) describe two cases of transmission by bites and lice. 



3. Diseases of Animal Origin 

Protozoa 

Mastigophora: Binucleata: Trypanosomidae 

Trypanozoon lewisi Kent (Trypanosoma, Lewisonella), a common 
parasite of rodents, often nonpathogenic, is transmitted by several species 
of fleas but Von Prowazek has demonstrated that it may also complete 
its development in the rat louse, Polyplax spinulosa Burmeister. The rat 
becomes infected by licking up the insect dejections. 

Mastigophora: Binucleata: Leptomonidae 

Leptomonas pediculi (Fantham) (Herpetomonas) is the only true 
louse parasite described. Fantham and Porter (1916) have even demon- 
strated this organism experimentally pathogenic to Mus musculus. It 
occurs in the alimentary tract of Pediculus corporis and P. humanus. 

Leishmania donovani (Laveran and Mesnil) is the cause of Tropical 
Leishmaniasis or INDIAN KALA AZAR. The normal carrier is unde- 
termined, but positive results have been obtained with the bedbugs, Cvmex 
hemipterus and C. lectularius. Patton and also Mackie have failed to 
get results with lice. Possibly these failures were also due to the con- 
duct of the biting experiments rather than scratching in experiments 
with lice and their feces. It would pay to reinvestigate the lice in connec- 
tion with the disease. 



LOUSE BORNE DISEASES 295 

Mastigophora: Spirochaetacea: Spirochaetidae 

Spiroschaudkmia carteri (Mackie) is the cause of ASIATIC RE- 
LAPSING FEVER. Mackie (1907) in India was the first to investigate 
the transmission of relapsing fever by lice. He found a striking coinci- 
dence between the cases of fever among Indian school children and the 
prevalence of lice (Pediculus corporis). Mackie found the spirochaete in 
14 per cent of the lice from the boys and 2.7 per cent of the lice from 
the girls. He noted that the spirochaetes multiplied within the gut of 
the lice and that they could be found in the ovary, testis and Malpighian 
tubules of the insects, but did not find them in the ova laid by infected 
insects. Bisset (1914) only found Spirochaetes in the gut and coelomic 
cavity of the lice. The organism, Spiroschaudirmia carteri Mackie, is 
considered as a biological species not morphologically separable from S. 
recurrentis. 

Spiroschaudkmia berbera (Sergent and Foley) is the cause of 
NORTH AFRICAN RELAPSING FEVER. Following up Mackie's 
work, Sergent and Foley (1908) in Algeria carried out experiments with 
lice and obtained positive results by the inoculation of a monkey (Cyno- 
molgus cynocephalus) with a single, crushed, infected louse (Pediculus 
corporis). Pediculus humanus has also been recorded as an intermediate 
host. Nicolle, Blaizot and Conseil (1912), also working in North Africa, 
found that when body lice were fed upon infected blood, the spirochaetes 
disappeared rapidly from the insects' intestinal tract within 24 hours. 
On the eighth to tenth day, typical, active spirochaetes reappeared in the 
lice. Thousands of lice were allowed to bite monkeys and a man with 
only negative results. Infection was obtained in one of the authors by 
crushing an infected louse on excoriated skin, the incubation period of the 
fever being five days. They determined in one experiment that the infec- 
tivity of the lice was hereditarily transmitted. Eggs laid 12 to 20 days 
after the parent lice had fed on relapsing fever blood were placed at 28° 
C. and began to hatch on the seventh day. The young larval lice and 
some unhatched eggs were now crushed and inoculated into a monkey 
which subsequently developed relapsing fever. The spirochaetes were 
not discoverable microscopically in the eggs. As the result of the work 
of Sergent, Foley, Nicolle, Blaizot, Conseil and others, it is proven that 
the lice are infective, though inconstantly, up to five days after an 
infective meal, and constantly on the sixth day, although during this 
period spirochaetes are absent ; on the eighth to ninth days the spiro- 
chaetes may or may not be present and infectivity is exceptional. After 
the spirochaetes become fully developed in the lice infectivity vanishes. 
They may be infective up to the fifteenth day. The apyrexial stage of 
the spirochaete in man and the developmental or granule stage in the 



296 SANITARY ENTOMOLOGY 

insect are so minute that they have not yet been demonstrated. The 
organism Spiroschaudinnia berbera Sergent and Foley is considered as a 
biological species, not morphologically separable from S. recurrentis. 

Spiroschaudinnia recurrentis (Lebert) causes EUROPEAN RE- 
LAPSING FEVER. Although many authors consider the above men- 
tioned relapsing fevers as identical with the European fever, the evidence 
of louse transmission was slow in coming. Manteufel (1907) found that 
the rat louse, Polyplax spinulosus, may carry the disease from rat to 
rat, and suggested that possibly Pediculus corporis could carry it to 
man. Other authors made similar suggestions. Finally Toyada (1914) 
found crushed lice infective for mice up to three days after they had fed 
on infective blood. Since the outbreak of the great war the conviction 
of the role of the louse as a vector of European relapsing fever has be- 
come very strong. In fact repressive measures used in Roumania against 
the louse were effective against the fever. This disease can also be car- 
ried by the bedbug, Cimex lectularms. 

Spiroschaudinnia duttoni (Novy and Knapp) causes RELAPSING 
FEVER OF TROPICAL AFRICA which normally is transmitted to man 
by the tick Ornithodoros moubata, but Neumann (1909) found that it 
could occasionally be transmitted from rat to rat by means of the rat 
louse, Polyplax spinulosus. 

Spiroschaudirmia sp., cause of MANCHURIAN RELAPSING 
FEVER, is claimed by Toyada (1917) to be transmitted by lice. 

Leptospira icterohemorrhagiae (Inada and Ido) causes INFEC- 
TIVE OR EPIDEMIC JAUNDICE, also known as Weil's disease which 
is infective to man and rats. In the European trenches the rat is re- 
garded as the reservoir of the disease. The spirochaete is excreted by 
way of the urine or feces of rats or men and is consequently easily com- 
municated through the trenches. It is readily communicated through 
the mouth or through abrasions in the skin (Dawson, Hume and Bed- 
son, 1917). Stokes conducted negative experiments with Pediculus cor- 
poris, but these experiments were not directed toward obtaining infec- 
tion through crushing or scratching lice or feces into abrasions of the 
skin. This phase of the subject will bear further investigation especially 
since Dietrich (1917) declares that the disease can be carried by 
Pediculus corporis. 

Telosporidia: Haemogregarinida: Haemogregarinidae 

Haemogregarina (Hepatozoon) gerbilli (Christophers) cause of the 
ANEMIA OF THE JERBOA, Gerbillus indicus in India, is believed 
by Christophers (1905) to pass its cycle of sporogony in the rat louse 
Polyplax stephensi C. and N. 



LOUSE BORNE DISEASES 297 

Haemogregarina (Hepatozoon) funambuli (Patton), cause of the 
ANEMIA OF THE PALM SQUIRREL, Funambulus pennatii in India 
was found in the vermicule stage in the gut and coelome of the louse, 
Haemotopmus sp., but further development was not observed. 

Metazoa 
Platyhelmia: Cestoda: Cyclophyllidea : Taeniidae 

Dipylidium caninum (Linnaeus), the DOUBLE-PORED DOG 
TAPEWORM, may have as an intermediate host the biting louse of the 
dog, Tricliodectes latus Nitzsch {canis De Geer) according to Melnikow, 
although it usually passes its intermediate stages in fleas. 

This completes the summary of the evidence which has so far been 
presented against the lice. There are many species of sucking lice of 
wild and domestic animals, and there are many obscure or little known 
animal diseases. It is naturally to be expected that the literature of 
animal disease transmission by lice will grow. 

I have attempted also to show that the majority of the louse-borne 
diseases pass through the body of the louse and out through the feces 
and that they gain access to the host in the following ways : the rubbing 
or scratching into a skin abrasion of infective portions of the insect body, 
or its dried or fresh feces ; the carrying of the contamination on fingers 
which have scratched the louse or its feces, and transfer of the contamina- 
tion on the fingers to the mouth or the eye ; the licking up of the lice or 
their feces by animals which cleanse themselves with the tongue. Direct 
transmission by bite apparently does not occur except possibly in typhus 
fever. 

It remains therefore to reiterate that all types of skin diseases and 
blood diseases in which the louse might be suspected should be reinvesti- 
gated in case the usual types of inoculation mentioned above have not 
been tried. 

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CHAPTER XXI 

The Life History of Human Lice * 
R. H. Hutchison and W. Dwight Pierce 

Until the outbreak of the great war there had been a great mass of 
desultory writing upon the three species of human lice, but this was in 
all languages and few had made any attempt to classify and arrange 
the knowledge thus obtained. Since the beginning of the war, however, 
the louse has been a major problem and there have been more titles pub- 
lished on it than on any other disease-carrying insect. The first compre- 
hensive work was published by Hase (1915-1916) in a series of papers. 
These were followed by several excellent monographs by Professor Nut- 
tall (1917-1918), the second of which gives a complete bibliography of 
the literature on human lice, a summary of the evidence of disease trans- 
mission, exclusive of the recent work on trench fever, and extensive 
biological studies. With the large number of students recently concen- 
trating on these vermin, we may expect that our literature will be 
greatly enriched with many more fine contributions. 

The human lice have generally been regarded as belonging to three 
different species, Pediculus humanus Linnaeus (capitis DeGeer), P. cor- 
poris DeGeer (vestimenti Nitzsch) (plate XXI), and Phthirus pubis 
Linnaeus (inguinalis Redi). Bacot carried out hybridizing experiments 
with humanus (capitis), and corporis, carrying the offspring to the third 
generation. It is on the strength of such studies that Nuttall united the 
two under the name humanus, and for convenience, designated one capitis 
(head louse), and the other corporis (body louse) as varieties of this 
species. Other writers are not wholly convinced in regard to the union 
of the two species and we shall await further studies with interest. 

The true P. humanus, or head louse, is usually confined to the head, 
mostly about the occiput and ears, but it may spread over the body, 
establish itself on other hairy parts, and may be confined to the pubic 
hairs and multiply there. The body louse, P. corporis, lives usually on 
the body and in the clothing and is very rarely found on the head. 
The pubic louse, Phthirus pubis, is usually found on the hairs in the 
pubic region but may occur in other hairy parts of the body. 

ir This lecture was presented June 17, 1918, and distributed the same day. It has 
been greatly revised. 

301 



302 SANITARY ENTOMOLOGY 

The body, head, and pubic lice are found on all races of men and 
seem to show some varietal differences according to the host. None 
of these species occurs on any other host than man, although a closely 
related species Pediculus consobrinus Piaget occurs on a monkey (Ateles 
jpentadactylus). 

Children and old people are much more likely to be affected with head 
lice than active men and women, and girls because of their long hair are 
much more frequently infested than boys. On the other hand, men 
seem to be more often the subjects of attack by corporis and pubis. 

In the civilian population of this country there are indications of im- 




Plate XXI. — The clothing louse, Pediculus corporis. Fig. 1. — Female, ventral view. 
Fig 2. Male, dorsal view. (Pierce and Hutchison, photos by Dovener.) 

portant changes in the general problem. In times of peace the louse 
problem is most acute in jails, poorhouses, and like institutions; among 
vagrants and the extremely poor classes ; among gangs of laborers, as in 
construction camps, lumber camps, threshing gangs, etc. ; and among im- 
migrants. Since our entrance into the war there have been economic 
changes which have shifted some of these centers of infestation. For 
example, there have been many camps of laborers engaged in temporary 
construction work. Reports indicate that lice give considerable trouble 
in some of these. There has probably been an increase in the size and 
number of lumber camps. On the other hand, we have been informed by 
the captain in charge of the House of Detention at New Orleans, that 
the vagrant population, which has always been their worst source of 



THE LIFE HISTORY OF HUMAN LICE 



303 



infestation, has been reduced more than two-thirds. It is also well known 
that immigration has been greatly reduced. 

The urgency of the problem in the armies led to extensive investiga- 
tions of control measures and of the biology of lice. The knowledge 
of the biology of the body louse was surprisingly meager up to the time 
the war began. It is our purpose in this lecture to call attention to some 
of the vital points in the biology of lice, and to point out their relation 
to practical control work, for without a knowledge of these points, one 
cannot expect to intelligently interpret the results of control work. Some 




Fig. 61. — Wristlet method used for breeding lice. (Hutchison, Photo by Dovener.) 



of the more important and recent additions to our knowledge of louse 
biology are due in no small measure to the improved technique for rearing 
lice as evolved by Bacot, Sikora, and Nuttall. Warburton's method of 
placing the insects on cloth in plugged tubes, feeding them twice daily 
and placing the tube in the pocket or incubator between feeds, has been 
largely followed, with modifications by other workers, but after many 
attempts at rearing lice under more normal conditions and providing them 
with unlimited opportunities for feeding, Nuttall finally worked out the 
two methods which he describes under the names of the "felt cell method" 
and the "wristlet method" (fig. 61). For the details of these methods it 
is best to consult the original description in Nuttall's (1917b) article on 
the biology of Pediculus humanus. In fact, we have avoided giving a 



304 SANITARY ENTOMOLOGY 

stereotyped account of the life history, on the assumption that this article 
will be read by all those interested. 

The first point to be noted is the fact that body lice may occur on 
the body as well as on the clothing. Nuttall has brought out convincing 
evidence that nits as well as lice themselves are often found upon the body 
hairs, especially in the axillae, the hairs of the breast, and at times on the 
pubic hairs and even the hairs of the thigh and leg. We have seen two 
cases in which both lice and nits were present in the axillae. The impor- 
tance of this point as regards control measures is obvious. Disinfection 
of the clothing is not sufficient, but must be accompanied by a thorough 
bath with some insecticidal liquid, such as cresol-soap, or the kerosene 
soap used by Boyd in his work with the Mexican laborers of the Sante Fe 
Railroad. 

Moreover, it was soon discovered from actual experience in this war 
that a disinfection of a part of the clothing was entirely ineffective ; for 
example, if clean shirts are provided, while the trousers have not been 
cleaned, lice quickly migrate from the trousers to the clean shirt which 
affords them new areas for deposition. Thus conditions are soon as bad 
as before. 

A second point having an important bearing on control measures 
is the number of eggs laid per female and their rate of development. The 
importance of the improved technique for rearing lice, mentioned above, 
consists in showing that previous statements, regarding the number of 
eggs laid, clearly underestimated their power of reproduction. When the 
lice are fed but twice a day only four to five or six eggs are obtained per 
day, while by the wristlet method Nuttall obtained as high as twelve eggs 
per day per female, the average being about ten. He states that cor- 
poris may lay 275 to 300 eggs during its lifetime. By the same method 
the senior writer has obtained as high as fourteen eggs per day, with an 
average of about eleven per day over a period of twenty-five days. 

The eggs are elongate, oboval, with a granulated cap or operculum 
at the outer end (plate XXII). They are cemented singly to a hair (in 
all three species), or a thread (P. corporis). Occasionally a single hair 
will be covered with them. Oviposition usually commences in P. corporis 
within two days after maturing. 

When a female is ready to oviposit she clings to a hair or thread, 
and slipping backward, grasps it also with the gonopods and the pos- 
terior lobes of the last segment. A drop of cement is excreted, followed 
by the egg, which is thus firmly cemented to the hair and the insect 
moves away. The entire operation consumes about 17 seconds. The 
operculum is usually directed away from the root of the hair. 

Oviposition takes place most readily at about 30° C. (86° F.) and 
ceases at 20° C. (68° F.). They lay rapidly at 37° C. (99° F.) although 



THE LIFE HISTORY OF HUMAN LICE 



305 




Plate XXII. — Eggs, of the Clothing Louse, Pediculus corporis. Fig. 1 (upper). — Mass 
of eggs, slightly reduced, between seams of trousers. (Photo by Dovener.) Fig. 

2 (center). — Great enlargement showing eggs hatching. (Photo by Paine.) Fig. 

3 (lower). — Very- great enlargement showing structure of eggs, with exuviae within. 
(Photo by Paine.) 



306 SANITARY ENTOMOLOGY 

this temperature shortens their lives. Infected persons who remove their 
clothing at night consequently become less heavily infested than those 
who wear their clothing continuously. The periodic cooling of the cloth- 
ing and the lice therein leads to their progeny being materially re- 
duced. 

Nuttall and Bacot are both agreed that capitis prefers to lay its 
eggs on hairs, but they do not agree as to whether corporis prefers cloth 
to hairs for oviposition. 

The length of the egg period varies from 5 to 16 days under normal 
conditions and may be retarded to the 35th day, or possibly later, by 
cold periods. Under European conditions of humidity, apparently 30° 
C. (86° F.) gives about the optimum condition for hatching, although 
the shortest period experienced was at 37° to 38° C. (99-101° F.). In 
experiments at New Orleans at 37° C, hatching occurred in four to 
eight days; while the eggs hatched in six to seven days at temperatures 
of 33° to 34° C, and in eight days at 30° C. The effective zone for 
the egg stage is from slightly under 20° to 40° C. (68-108° F.). At 
temperatures of 40° to 45° C. the embryo dies. In this connection, 
Nuttall has made some very unfortunate remarks. He discredits the 
seven-day record with two individuals at 20° C. made by Widmann, the 
ten to twelve-day records at the same temperature made by Heymann, 
and Legroux's statement that they rarely hatch at 16-18° C, because 
Sikora and Hase recorded failures at 20° and Nuttall and Hindle failed 
to hatch eggs at 22° C. It is quite possible at 20° C. at one humidity 
to obtain death ; at another humidity, 12-day development ; at another, 7- 
day development ; and at still a different humidity, possibly a very long 
developmental period. All of Nuttall's remarks on temperature effects 
must be more or less discounted because of his ignoring the important 
humidity factor. In fact, he states that there is no evidence that eggs 
maintained at 22° C. or under are capable of hatching, but he quotes 
quite a series of retarded development records in which the eggs were 
maintained for more or less long periods at low temperatures. For in- 
stance, Widmann kept eggs for 24 hours at 10° C, and then transferred 
them to 26-30° C, and they hatched in 17 days. After keeping eggs at 
9° C. for two or three weeks, Heymann transferred them to a favorable 
temperature and they developed in 15 days. The length of time the eggs 
can stand a given low temperature will depend to a large measure on the 
humidity. At a given temperature it appeared that dryness may retard 
development two or three days or more. Thus it may be seen that there 
is still work to be done on the effect of humidity on the incubation period. 

In testing various insecticides for their effect on the eggs, it is neces- 
sary to provide the proper temperature conditions; otherwise, failure to 



THE LIFE HISTORY OF HUMAN LICE 307 

hatch may be due to low temperature rather than to the chemical or other 
agent tested. 

In interpreting results from control experiments, it is important to 
bear in mind that lice will lay infertile eggs. Isolated females to which 
males have not had access will lay eggs at about the normal rate. Such 
eggs are all sterile and show no development. There is no evidence of 
any parthenogenesis. But even females to which males have had access 
will lay some infertile eggs especially near the beginning and end of their 
lives. Nuttall says that at constant temperature of 30° C. we may 
expect about 70 per cent of a given lot of eggs to hatch. Of those which 
fail to hatch, some are fertile, some undergo partial development, but 
for some unexplained reason fail to complete development. He points out 
that "hatching alone is not therefore a true test of fertility." For accur- 
ate work, eggs of known age should be used, preferably after they have 
reached the stage when the eyes appear as faint brown spots on each 
side of the head of the embryo. By examination with the binocular, the 
presence of these eye-spots will indicate the number which are fertile, and 
their absence, the number sterile. 

The freshly laid egg is almost transparent, but as the embryo de- 
velops, the egg assumes a yellowish color and the eyes first appear as 
pinkish spots, gradually turning red or brown in color, finally becoming 
black. After the limbs become clearly defined and the claws and eyes 
darken, there are slight movements of the limbs, and of particles within 
the body of the embryo, and periodic pumping movements of the pharynx 
begin to appear. These pumping movements become more frequent as 
time for emergence approaches. Sikora and Nuttall were the first to 
grasp the meaning of these pumping movements and show that they 
are intimately concerned with the act of emergence. When the larva is 
ready to emerge, the air is pumped in rapidly through the so-called air 
canals of the operculum. The air is accumulated in the anterior end of 
the shell, the body of the embryo completely filling the remainder. As 
pumping continues, the air is passed on through the gut, "the bubbles 
being distinctly seen through the transparent glassy shell as they pass 
backward" and are expelled through the anus and accumulate in the pos- 
terior end, thus pushing the embryo up against the operculum. "This 
pressure of the air cushion finally overcomes the resistance of the oper- 
culum and the latter springs open." The head of the larva is thus forced 
out and assumes a normal position. Soon the first pair of legs is with- 
drawn. These are quickly brought into action and with their aid the 
remainder of the body is soon withdrawn. This highly interesting 
process is important in its relation to control measures. In the first 
place, if oily or greasy substances are used they occlude the air canals 
of the operculum and the larva dies. Some substances when applied to 



308 SANITARY ENTOMOLOGY 

young eggs, may evaporate without acting directly on the embryo and 
leave the air canals open by the time the embryo has reached the stage 
of pumping movements. In control experiments results have been ob- 
tained which indicate this, the mature eggs being destroyed and the 
younger eggs emerging some days later, showing that the chemical had 
not affected the contents of the egg, but killed the older eggs by occlusion 
of the air canals, and passed off in time to permit the younger ones to 
hatch. 

Another point of importance is that proper temperature conditions 
must be provided in such experiments, to permit normal emergence as 
well as normal incubation. If the temperatures are too low the process 
of emergence is slow and the vitelline membrane will dry before the larva 
has freed itself. As a result the larva dies with the head and first pair 
of legs and part of the thorax outside the shell, but the posterior end 
of the body and the second and third pairs of legs stick to the dried 
membrane, or it may be that the larva will die without bursting the mem- 
brane. In some cases larvae have been found with all but one leg free 
from the membrane, but this so firmly stuck fast as to prevent escape. It 
is important, therefore, to bear in mind that the effect of low temperatures 
may entirely outweigh the effect of the control measure under trial. Ef- 
fective temperature is higher than for most other insects. 

The egg shell is very tough and resistant to chemicals as is also 
the cement by which it is fastened and there is no known way of removing 
them without first destroying the fibers or hair to which they are attached. 
Hase describes how the Russian prisoners tried to reduce infestation by 
hanging shirts on a wire and beating with sticks, and Legendre recom- 
mends vigorous brushing with a stiff brush. Hase is doubtless correct 
in pointing out that beating fails to dislodge many of the lice or to crush 
any of the eggs and that brushing may tear loose some fibers with at- 
tached eggs, but actually destroys very few. On the contrary, it is 
pointed out that this may be the means of spreading the infestation to 
other men rather than affecting any reduction. Hase carried out experi- 
ments showing that lice can crawl up to the surface after burial in sev- 
eral inches of dry sand or earth. If shaken or beaten out of the clothing 
to the ground and pressed into the sand under the heel they will crawl 
to the surface and attach to the first host near them, which they have 
abundant opportunity to do in a crowded prison or prison camp, espe- 
cially when the weather permits the prisoners to lie down on the ground. 
Eggs brushed from clothing will hatch if temperatures are favorable, and 
the issuing larvae reach new hosts in the same way. 

Many experiments have been carried out b}' Hase and Nuttall with a 
view to determining what kind of materials lice prefer for oviposition. 
They agree in showing that rough materials such as felt, wool, and flannel 



THE LIFE HISTORY OF HUMAN LICE 309 

are preferred. However, in case of necessity, the lice can and will oviposit 
on smooth materials such as silk and sateen. It has been suggested that 
infestation could be greatly reduced and even remedied entirely by wear- 
ing for one to twenty -four hours a broad band of felt or rough wool under 
the clothes, with the idea that lice would collect on this, and they and 
their eggs could then be destroyed by burning. But the preference of 
lice for such material, and the difference between this and the uniform is 
not marked enough to make it really effective. 

In practical control work the question is likely to arise as to how 
long discarded but untreated clothing will remain infective. The an- 
swer to this, of course, depends on how long lice can live without food 
and how long it takes for all the eggs to hatch. Experiments show 
that lice can live without food from two to three days at 35° C, three 
days at 30° C, three to five days at 22° C, and about seven days at 
10° C. The lice cannot live long without food unless at ineffective tem- 
peratures, the longest period recorded being ten days at 5° C. 
(41° F.). The longest record of fed adults is 46 days for a female 
recorded by Bacot. One male lived 32 days and fertilized eighteen females. 

As stated above, eggs will hatch in sixteen days at 25° C, but 
below 22° C. they usually do not hatch. How long a period of low tem- 
peratures they can endure, and still hatch when the temperature is again 
raised, is not known beyond a statement by Nuttall that he delayed hatch- 
ing to 35 days by low temperatures. Certainly the safest plan would be 
to allow 30 to 40 days of cool weather or* two weeks of hot weather for 
all the eggs in discarded clothing to hatch. 

There are three larval stages, or possibly we may call the last the 
nymphal stage. The larvae suck blood from their human host. The first 
molt occurs on the third to eighth day, and the other stages are corre- 
spondingly long. 

In molting, the skin splits longitudinally from base to apex of 
thorax and along the base of the head to near the base of the palpi. 

The entire life cycle of corporis on the human body may be as short 
as sixteen days, eight for the egg, two each for the first and second larval 
stages, three for the third stage, and one day preovipositional period. 
The head louse has been carried through its entire life C3^cle in seventeen 
days. 

The frequency with which lice feed is dependent upon the rate of diges- 
tion, which is dependent upon climatic conditions. They feed more fre- 
quently at body temperatures than when kept cool. They feed at all 
times of the day. Lice which have not had a feed for some time become 
ravenous and often feed to excess, rupturing the intestines and causing 
death. 



310 SANITARY ENTOMOLOGY 

The lice seem to avoid light except when hungry. They seem to 
be quite sensitive to excessive warmth and will leave a fever patient. 

In the absence of definite humidity data we may roughly describe 
the zones of climatic influence on the lice as follows: The zone of mini- 
mum fatal temperatures for eggs is below 20° C. (68° F.) and for adults 
lies below zero centigrade (32° F.). The zone of the dormancy in adults 
extends from about -10° to 5° C. (14° to 41° F.). The zone of slug- 
gish movement without reproductive activity and with practically no 
digestive processes extends from 5° to 20° C. (41 to 68° F.). Digestion 
ceases at 12° C. The zone of optimum activity lies between 20° and 40° C. 
(68° to 140° F.) with the optimum about 30° C. Practically all egg 
hatching occurs within this zone, as does all oviposition, practically al] 
assimilation of food, and all normal activity. From 40° to 44° C. the 
lice are wildly active. This zone represents one of exhaustion in which 
death of eggs occurs. Above 44° C. (112° F.) lies the zone of maximum 
fatal temperatures. In control work 54° C. (131° F.) for one-half 
hour is sufficient to kill all stages, and 60° C. (140° F.) for one-quarter 
of an hour gives a very thorough control. 

There are several other phases of the biology of lice which may be 
mentioned briefly. For example, the locomotory powers would repay 
study. Their inability to make any headway on clean smooth metal or 
glass when inclined at an angle of more than 2° to 3°, and their inability 
to crawl on smooth vertical surfaces such as rubber gloves or boots, as 
contrasted with their gymnastic skill on threads or fibrous materials 
and their power of clinging to anything which they can clasp with their 
claws, explain the different protective uniforms worn by those who have 
had to do with typhus epidemics. 

Their different reactions to light when fully fed or when hungry have 
a bearing on the question as to how they find new hosts. 

There are yet many phases of the biology which need elucidation. 
For example, the question as to the state of development of the olfactory 
sense and whether this comes into use in finding a new host. Hase con- 
cludes that they have a fairly keen olfactory sense because they are 
quickly repelled by substances like tar and ethereal oils. According to 
him, they recognize and avoid the odor of horses, — the clothing of those 
artillery men who drive and care for the horses is saturated with the 
horse odor and free from lice, while others in the same battery without 
the horse odor are infested. On the other hand, a hungry louse placed 
on a glass slide near a freshly drawn drop of blood is apparently entirely 
unaware of the proximity of food. Likewise a hungry louse on a piece 
of cloth is apparently unaware of the presence of a human hand and a 
chance to feed, until a finger has been pushed within one-half inch or 



THE LIFE HISTORY OF HUMAN LICE 311 

less of it, and that may be a positive reaction to the heat radiation from 
the hand rather than an odor reaction. 



REFERENCES 

Hase, A., 1915. — Beitrage zu einer Biologie der Kleiderlaus. Zeitschr. f. 

angelwandte Entomol., Band. 2, Heft 2, pp. 265-359, 47 figs. 
Hase, A., 1915. — Weitere Beobachtungen liber die Laiiseplage. Centralb. 

f. Bakteriol. Parasitenk u. Infektionskr., 1 Abt., Orig., Band. 77, pp. 

153-163. 
Hase, A., 1916. — Ueber die Entwickelungstadien der Eier und ueber die 

Larven der Kleiderlaus. Naturw. Wochenschr., Band. 31, pp. 1 et seq. 

(inaccessible), 
Nuttall, G. H. F., 1917. — Studies on Pediculus. Parasitology, vol. 9, pp. 

293-324, 2 pi., 12 text figures. 
Nuttall, G. H. F., 1917b.— Parasitology, vol. 10, No. 1, pp. 1-183. Sev- 
eral articles including complete bibliography. 
Nuttall, G. H. F., 1918.— Parasitology, vol. 10, No. 3, pp. 375-405, 

figs. 1-5. 



CHAPTER XXII 

The Control of Human Lice * 
W. Dwight Pierce and R. H. Hutchison 

Never in the history of the world has the subject of insect-borne 
diseases become so prominent as it has since the discovery that several 
of the great diseases which ravage nations and armies are borne by 
lice, and that personal prophylaxis alone will combat these diseases. 

The knowledge of the means of conveyance of a disease is the first 
requisite for the successful preventive measures. Had the scientists not 
known how typhus fever was spread the entire nation of Serbia, and pos- 
sibly most of the peoples of eastern Europe and the poor peoples of all 
the war-stricken nations as well as the men in the trenches might have 
been wiped out by now. As a matter of fact, probably one-third of the 
Serbian nation and hundreds of thousands of Roumanians, Austrians, 
Russians, Germans, and Turks were lost before the medical authorities 
obtained the necessary grip on the situation. The lice would have gone 
on disabling the men in western trenches with trench fever if they had not 
been proven to be the vectors. 

THE RAVAGES OF LICE 

The eastern theatre of war has long been scourged with louse-borne 
epidemics. During the Crimean war the British troops became seriously 
infested, becoming anaemiated and debilitated and death carried off many 
of them. The only remedy available was to put the wet flannels in the 
snow for two days — this killing all but the nits (Shipley). 

Typhus fever ravaged the Bulgarian troops during the two Balkan 
wars to such an extent that it was estimated by a staff officer that they 
lost more soldiers in a short period of time from fleck typhus than from 
all other diseases combined. 

During the present war, the lice at first were most serious in the 
eastern theatre, probably due to the greater congestion of population 
among the Slavic peoples. The Germans first had to combat them among 
the Russian prisoners, finding the French almost completely free. But 

1 This lecture is a modification of one rend June 24 and distributed June 27 and of a 
synopsis presented September 18 and distributed October 4, 1918. 

312 



THE CONTROL OF HUMAN LICE 313 

by mixing the prisoners, and the exchange among them of souvenirs, espe- 
cially shoulder straps under which the lice clung in masses, the lice 
became generally distributed. It was not long before the German armies 
found the louse a very live problem and their scientific journals are full 
of papers on the control of the vermin 

In Serbia a few cases of typhus fever occurred in October, 1914, 
and in January, 1915, the disease was epidemic among Austrian prisoners 
who were greatly crowded and necessarily compelled to live under very 
unsanitary conditions. The disease quickly spread from them to other 
individuals, and as there was no quarantine, and the Austrian prisoners 
and the infected individuals were sent or allowed to go to various parts 
of the country, Serbia was soon afflicted with a terrible and widespread 
epidemic. Weakened by the ravages of war, the country was not pre- 
pared for an epidemic and for a time typhus raged almost at will. The 
majority of the Serbian doctors, who were few in number, became afflicted. 
The epidemic was at its height in April when the number of cases was 
at least 9000 a day, but it was impossible to gauge the number of cases 
in the rural districts. At least 100,000 men, or a quarter of the army, 
were destroyed in this epidemic which was checked by the energetic efforts 
of the medical officers, assisted by Dr. R. P. Strong and his American 
colleagues. The work of the Serbian Sanitary Commission is briefly de- 
tailed by Doctor Strong in various reports. 

In Roumania typhus fever and relapsing fever became epidemic in 
the winter of 1916-17 and the conditions which occurred there are very 
vividly portrayed by Wells and Perkins (1918). Rulison (1918) gives 
the history and statistics of the epidemic from its beginning through the 
greater part of 1918, estimating 26.000 deaths from typhus fever up to 
February 13, 1919. 

It was inevitable that the louse should reach the western trenches 
and contaminate them with disease, and we find that trench fever was 
soon considered the most disabling disease of this front. Reports show 
that a very high percentage of the men in the trenches became verminous. 



RESERVOIRS OF EOUSE BREEDING 

Before discussing the control measures, we must also know whence 
arise these infestations of lice which can infect whole nations, because 
prophylaxis must take into account the reservoirs of the pest. In the 
L^nited States, where cleanliness and bathing are more or less the gen- 
eral rule, there have never been great outbreaks of these vermin except 
in time of war. In certain parts of the world, however, the louse is an 
ever-present associate of man. This is especially true of the ignorant and 
the densely populated portions of the world, the Mexican and South 



314 SANITARY ENTOMOLOGY 

American peons, the European peasants, the Mohammedan populations 
of Africa and Asia. Among the Mohammedans, their religion forbids 
killing insects and from childhood they become inured to their attack. 
War serves to aggravate conditions by concentrating refugees and pris- 
oners in crowded, unhygienic zones, and by mixing troops from all stations 
of life and from all races. Among our own people, lumber camps, min- 
ing communities, jails, poorhouses, lodging houses, construction camps, 
ghettos, negro communities, Mexican colonies, Indian reservations, tramps, 
and vagabonds are the principal reservoirs of infection which infect our 
armies and the civil population. Ignorant, degraded people everywhere 
are sources of lice. Our public schools, where children from all strata of 
society mingle, furnish constant trouble as distributing centers of head 
lice, as the children's hats and clothing hanging on racks afford easy 
means of spreading the vermin. Infection from lice may occur as just 
mentioned in clothes racks, public transportation, public halls, public 
toilets, hotels and lodging houses, and by coming in direct contact with 
lousy individuals. 

CONTROL MEASURES 

Out of conditions as described above have arisen heroic methods of 
treatment. When things are done in armies they must be done on a large 
scale. Consequently we find that Dr. Strong's commission began 
to educate the Serbian nation on the necessity of bathing and cleansing 
the wearing apparel, and similar efforts were later made in Roumania. 
And furthermore, with the cleansing came the control of the epidemics. 

The British in 1915 began isolating German prisoners for 14 days 
after capture, for observation, and they treated or destroyed their 
clothing and bathed them as promptly as possible. The isolation of 
prisoners was later practiced quite generally. 

It has become a well-defined principle now that new acquisitions to a 
military camp must be treated for lice. This treatment is called de- 
lousing or disinsection. Men returning from the trenches, prisoners of 
war, men who have- been on furlough, new recruits, and new units must 
be inspected and given a complete delousing treatment on general prin- 
ciples. This treatment often varies in detail but consists of thorough 
bathing, cleansing of the clothes and accoutrements, and disinfection 
of bedding and baggage. 

On the Mexican border the United States Public Health Service has 
found it necessary to exercise a rigid supervision over refugees from 
Mexico, as the disturbed political conditions in that country have re- 
sulted in a spreading of typhus fever from the plateau regions, where it 
is endemic, to all parts of the country. The immigrants are stripped and 
given identification tags for their clothing and baggage, and then they 



THE CONTROL OF HUMAN LICE 315 

themselves are given thorough spraying with kerosene or gasoline emul- 
sion, and then baths with warm water, and if lice are present, the hair 
of the men and boys is clipped and burned. The women have a mixture 
of equal parts of kerosene and acetic acid applied to the hair for half an 
hour with a towel covering the head. The acetic acid loosens the eggs 
from the hair and the kerosene kills or stupefies the lice. Before enter- 
ing the bath, liquid soap is sprayed on each person. The soap is made 
by boiling one part of soap chips in four parts of water and then adding 
two parts of kerosene oil, or four parts of gasoline. This jellies when 
cold, and one part of this soap jelly is added to four parts of warm 
water, making a good liquid soap at very small cost. The clothing is 
disinfected by being placed in bundles in the steam chamber, in which a 
vacuum of 10 to 15 inches is created, and live steam is then introduced 
until the gauge shows 20 pounds, which gives a temperature of 259° F. 
This is maintained for 10 minutes to insure penetration. The creation 
of a second vacuum of 10 inches and holding it for 10 minutes will dry 
the clothing completely. (Pierce, C. C, 1917.) 

Recent studies have shown the inadequacy of gasoline and gasoline 
emulsion as an insecticide, and it is therefore our recommendation that 
only kerosene emulsion be used in delousing. (See Hutchison and Pierce 
1919.) 

There are certain general methods by which much of value in insect 
control can be gained, and many of these can be classed as educational. 
An educational propagandum has been conducted in practically every 
one of the nations most seriously affected and also in the United States. 
Press statements, magazine articles, bulletins and lectures, posters, and 
personal demonstrations have done much to reduce louse incidence, and 
finally, the moving pictures used by the War Department to educate 
the American troops, have vividly brought to their minds the dangers and 
the means of control. 

Personal prophylaxis, when one is subject to louse infection, may be 
regarded as one of the best means of keeping free of them. This should 
consist of daily or weekly baths, according to convenience ; frequent 
change and laundering of underclothing, and dry-cleaning of outer gar- 
ments ; frequent personal inspection of clothing, especially along the 
seams. In military commands where practicable, there should be weekly 
official inspection of a very thorough nature. Many inspectors make the 
mistake of looking at the man for body lice, instead of in his clothing. 
For crab or head lice an inspection of the person is of course the only 
means of detection. 

Inspection for lice must not be considered essentially an army prac- 
tice. Any jail, hospital, lodging house, poorhouse, orphanage, or other 
charitable institution, is more than likely to receive many lousy inmates. 



316 SANITARY ENTOMOLOGY 

Either there must be a thorough system of inspection on entrance, or all 
applicants must be assumed to be infected, and accordingly bathed and 
have their clothing sterilized. 



CONTROL OF LICE ON THE BODY 

Control of Crab Louse 

The crab or pubic louse is confined usually to the hairy portions of 
the body, including the head and the eyebrows. Its eggs are attached 
to the hairs, and the lice themselves remain fixed to the body, with the 
head imbedded. Prophylaxis for it is therefore largely personal. The 
infected person should bathe in hot water and use an insecticidal soap 
such as the kerosene emulsion soap described above, and then anoint the 
infected parts with yellow oxide of mercury ointment, mercurial ointment 
(blue ointment), carbolic acid 2 per cent followed by olive oil, or vermi- 
jelly made up by the following formula: 

Texas fuel oil, sp. grav. 0.86, b. p. 250 to 350° C 50 parts 

Crude vaseline 20 parts 

Soft soap 30 parts 

The cutting or shaving of pubic or axillary hairs is to be avoided 
because of the discomfort caused. Powders such as N. C. L, etc., should 
not be used in the pubic regions. 

Control of Head Louse 

The head louse is usually confined to the head and lays its eggs on the 
hairs. The usual approved prophylaxis consists of daily combing and 
brushing and periodic washing. It is well to keep children's hair short. 
Many children's institutions clip the boys' hair, and clipping of hair is a 
common military practice. Several insecticidal hair washes are used: 

1. Wash head with equal parts of kerosene and vinegar or 25 per 
cent acetic acid for one half hour, keeping the head covered with a towel. 
The vinegar separates the eggs from the hairs, while the kerosene kills 
them. Use a fine-toothed comb to remove the eggs and lice. Wash the 
head with warm water and soap containing kerosene (Nuttall). 

2. Have patient lie down with the head over edge of bed above a 
basin resting on a chair, so that the hair lies in the basin. Pour the 
carbolic water over the hair so that it falls into the basin and sluice it 
about until the hair is soaked, for ten minutes. Drain, wring out mod- 
erately, and wrap head in flannel towel. After an hour wash the hair or 



THE CONTROL OF HUMAN LICE 317 

let it dry with the carbolic in it. To remove the eggs, apply 25 per cent 
acetic acid and use fine comb (Nuttall). 

3. Anoint head with a mixture of equal parts of kerosene and olive 
oil, wrap the head in a towel and sleep in it. Apply vinegar and remove 
eggs with a fine comb, then wash out with warm water and soap. This 
ma}' be repeated for two or three nights if necessary. 

4. Hair oil and pomades, as used in certain classes and races, are 
efficient. 

Control of Body Louse 

The body louse occasionally lays its eggs on the hairs of the body, 
but most of the measures involving treatment of the body are aimed at 
preventing attack. In handling this louse it must be borne in mind 
that simultaneous with freeing the body there must be control of the 
infection in the garments and living quarters. 

The bath is the first important step in control of the body louse. 

Bath Out-jits. — Early in the war it became apparent that portable 
bathing and disinsecting apparatus must be developed. In Russia, Brink 
(1915) late in November, 1914, devised a portable traveling bath capable 
of bathing a regiment of 4000 to 4500 men in l^/o to 2 days. 

Many modifications of this have been devised but we may give in 
general a composite of these, which may serve as the model. 

The outfit may consist of a wagon train with tents or portable huts, 
or a train, or at halting stations may consist of permanent structures. 
The portable wagon or tractor-drawn outfit can most nearly approach 
the trenches and is considered the best by Brink. The equipment should 
be capable of washing and cleaning the clothing and equipment of at least 
100 men an hour and to discharge each man in about half an hour, thus 
making it possible to wash an army unit in the course of a short 
time. 

There is also supposed to be a distinct separation between unclean 
and clean, and the cleaned men must not mix with the uncleaned. 

Disrobing. — In a bathing unit, the men come into the receiving tent, 
car, or room, and undress, receiving numbered tags for identification of 
their belongings. In the disrobing room each man .places his clothing 
in a bag, his accoutrements in another receptacle, personal belongings 
which do not need fumigation in still another, all of these receptacles 
bearing the number given to him. These articles may be treated in 
various ways as described under the various headings. 

Bath. — The men proceed into the bathroom and receive either shower 
or tub bath, and in some cases pass through several baths. In the Rus- 
sian portable outfits the bath equipment consists of folding benches, zinc 
covered tubs, wash basins, spoon measures for liquid soap, sacks for 



318 SANITARY ENTOMOLOGY 

sterilization of clothes, little numbered tags, canvas folding tanks for 
water, kerosene lamps to be used at night, and a barber shop. Naphtha 
soap is used as the cleansing agent. On the Mexican border at El Paso the 
men are first sprayed with gasoline soap (for which kerosene soap should 
be substituted) and then walk through a continuous spray in a tank of 
water about a foot deep. On the Sante Fe Railroad, according to Boyd, 
the Mexicans are given a ten-minute bath in kerosene and soap-suds 
(equal parts), with a kerosene and vinegar bath for the hair. Our own 
army has now established elaborate bath and disinfection houses. 

In at least one of the baths hot water should be used. The liquid 
soap described above, applied as a spray, is a very good method and 
prevents contamination by means of the soap. 

Either before or after the bath, they enter the barber shop, where 
the hair is clipped if there is any evidence of head lice. Bags should be 
tied around the neck to catch the hair, which is burned. The men may 
also be shaved. 

They then pass into the dressing room where they receive clean 
underclothes and their outer garments and other possessions disinfected 
and disinsected. 

Soaps. — In the bath, soap is one of the essentials. All soaps are not 
insecticidal, and others are not sufficiently effective. Recent tests have 
shown that gasoline and gasoline soap emulsion are not thoroughly effec- 
tive remedies (Hutchison and Pierce). The following soap formulae are 
considered effective: 

1. Liquid kerosene soap emulsion made by boiling one part soap 
chips in four parts water and then adding two parts kerosene oil. This 
jellies when cold, and one part of this jelly added to four parts of warm 
water makes a good liquid soap at very small cost. 

2. Five per cent carbolic acid and soft soap, equal parts. 

3. 5 per cent cresol and soft soap, equal parts. 

4. Two per cent lysol and soft soap, equal parts. 

For wounded men, after a shower, Adler-Herzmark recommends soap- 
ing down with a brush, using an emulsion of petroleum 1 part, soft soap 
2 parts, and lysol solution 1 part. Afterwards apply 3 per cent cresol 
ointment to the hairy parts. 

Sponge Baths. — It is often impossible for soldiers, especially, to get 
a genuine bath, so they must resort to sponge baths and treatment of 
the body and garments to reduce, at least, the infestation. 

A good treatment consists of sponging off the body with water, using 
the above-mentioned kerosene emulsion soap, or sponging with 2 per cent 
crude carbolic acid solution, and then anointing the body with ordinary 
grease or with vermi jelly, which we have already described. 

Vermicides and Repellents. — When unable to follow out the plan of 



THE CONTROL OF HUMAN LICE 319 

bathing and cleaning the clothing, the only means left is to use some 
kind of vermicide or repellent. Nuttall has described experiments with 
many chemicals, but Moore has gone into the subject much more exhaus- 
tively. Both reported unfavorably regarding sachets, although the fol- 
lowing substances have been found to exert repellent action on the lice: 
oils of anise, cloves, eucalyptus, naphthalene and carbolic acid. Insec- 
ticidal powders are frequently favored. Moore (1918a) lists many 
effective powders but reports the most effective to be made of: 

Creosote 1 cc. 

Sulphur % g r - 

Talc 20 gr. 

Naphthalene is very commonly used and is effective, but its continu- 
ous use may injure the eyes. One of the commonest powders in general 
use is known as N. C. I. powder and is made of : 

Naphthalene 96 per cent 

Creosote 2 per cent 

Iodoform . . . 2 per cent 

The specialists of all the nations have sought to find a substance 
with which clothing could be impregnated and rendered vermicidal. 
Moore has suggested wearing a cheesecloth suit impregnated with satu- 
rated solution of sulphur in creosote on the outside of the underwear, bu b 
on the whole he reports (Moore, 1918b) after testing many substances, 
that the cost of application is too high for the results obtained, and 
none are effective longer than a week. Moore and Hirschfelder subse- 
quently reported more hope of success from naphthalene and cresol com- 
pounds than from anything else. 

CONTROL OF LICE IX CLOTHING 

In order to properly delouse a unit, the cleansing of the clothing is 
of utmost importance. There are many satisfactory systems of treat- 
ment and it is therefore a question of choosing the one which is most 
practicable under the existing conditions. 

1. Laundry 

The laundry method of disinsection as described by Pierce, Hutch- 
ison, and Moscowitz, is the best and most efficient, given sufficient time 
and the necessary equipment. In this process the clothes are deloused, 
disinfected, cleaned, and pressed. Every step in the laundry is in- 



320 SANITARY ENTOMOLOGY 

secticidal. Laundries are to be found in all American cities and have 
been installed in practically all American cantonments and are found in 
many European centers. Portable steam laundries) were used by the 
American army, and in the future ( should always be a part of an army's 
equipment. There is no resulting damage to the garments if carried out 
as described below, which is according to standard laundry practice. In 
all ordinary cases, the following formula is sufficient for the treatment 
of woolen goods: 

1. Wash fifteen minutes at 131° F. in heavy suds and light load. 

2. Rinse three times, three minutes each, at 131° F. 

3. Extract. 

4. Run in drying tumbler fifteen minutes, at a minimum of 140° F. 
The goods should not be perfectly dry when removed. 

5. Iron. 

In case the garments are suspected of containing very resistent disease 
germs, the regular washing formula may be preceded by one of the 
following measures : 

a. In the washer, run a current of live steam fifteen minutes, revolv- 
ing cylinder every five minutes, and discharging water of condensation 
every five minutes. Remove the garments and shake until almost dry. 
Then turn the hot water into the washer and when the proper tem- 
perature is reached, put in the garments for the wash as described 
above. 

b. In the washer, submerge in water at 165° F. for twenty minutes 
without motion, except a few revolutions every five minutes. Remove 
the garments until the new water has been brought to 131° F. and then 
begin the wash as described above. 

Flat work, khaki and cotton underwear are washed by formulae 
requiring hotter water and are hence thoroughly disinfected and dis- 
insected. 

%. Dry Cleaning 

Uniforms and overcoats may be preferably dry cleaned rather than 
washed because of the stain-removing value of the dry cleaning process 
(Hutchison and Pierce, 1919). In this process the garments are de- 
loused, disinfected, cleansed, have stains removed, and are pressed. Dry 
cleaning establishments exist in most large cities. Many of the army 
cantonments had them installed and some units went overseas with our 
troops. 

This process is not insecticidal in every step, but is essentially so 
in a complete process. The gasoline wash, contrary to expectations, will 
not kill all submerged eggs, even after 54 hours. 



THE CONTROL OF HUMAN LICE 321 

a. For an establishment fully equipped with rotary washers and dry 
tumblers, we recommend the following cleansing formula : 

1. Wash goods 30 minutes in new, distilled, or clarified benzole, 
naphtha, or gasoline, having a specific gravity not less than 56° Baume 
by hydrometer test ; using one gallon of cleaning fluid to every two pounds 
of goods, two ounces of standard dry cleaning soap to every ten pounds 
of goods, one ounce of 26 per cent ammonia to every twenty-five pounds 
of goods. 

2. Extract 3 minutes. 

3. Rinse 15 minutes in new or distilled fluid. 

4. Extract 3 minutes. 

5. Dry in tumbler 30 minutes at a temperature not less than 160° F. 
at point of discharge from tumbler. 

6. Iron. 

In case drying rooms are used in place of tumblers follow the first 
four steps and then: 

5. After thoroughly drying and deodorizing, hang in dry room at 
temperature of not less than 160° F. for 30 minutes. 

6. Run in dust wheel 20 minutes. 

7. Iron. 

b. In case the dry cleaning establishment is not equipped with 
modern machinery, the following method will be practicable: 

1. Soak in benzole 3 hours. 

2. Wring out and dry. 

3. Iron thoroughly. 

This modified process is too long for army practice but will do for 
small commercial trade. 

c. Dry cleaning establishments equipped with Barbe system machin- 
ery in which hot gasoline is used in the wash, have a thorough insecticidal 
process in every step. 

3. Steam Sterilization 

The process of sterilization most commonly used in army practice in- 
volves the use of steam in some form. There is probably more danger to 
clothes from the use of steam than from any other method of treatment. 
Unless properly applied, steam will shrink, wrinkle and discolor woolens. 
It is probably by a few minutes the quickest process of sterilization, but 
steam does not cleanse or remove stains. When we consider that a uni- 
form must often be subsequently treated either by laundry or dry clean- 
ing to make it look presentable, we can readily see the advantage of 
using one of these processes for the entire operation of sterilization and 
cleansing. There is a proper way of handling each of the steam pro- 



322 SANITARY ENTOMOLOGY 

cesses to avoid the greater part of the damage. Nuttall (1918) has 
given a very exhaustive study of the methods of steam sterilization, 
especially with reference to autoclaves, so we will content ourselves with 
merely citing the most approved formulae. 

a. Live or current steam fumigation was proposed by Stammers, who 
devised the Serbian barrel. Hunter (1918) has given a rather full 
description of several of the dominant types. Exposure to live steam 
20 minutes in any kind of chamber is sufficient if the clothes are loose 
and permit circulation of the steam. Care must be taken not to over- 
load. 

The first method described below utilizes the laundry wash wheel and 
was devised by Pierce, Hutchison and Moscowitz. It is probably the 
quickest method yet proposed. The three other methods were described 
by Hunter. 

1. The live steam sterilization in the wash wheel has been described 
in the discussion of the laundry process, and only requires fifteen minutes. 
The clothes must not be packed any tighter than for a normal washing 
load. They must not be tumbled except once in five minutes to remove 
water of condensation. When taken out of the wheel they should be 
shaken well before hanging up to dry. 

2. Stammers' barrel disinfection, called the Serbian barrel, is a 
practicable field disinfector available often where no other sterilization 
can be carried out. It consists of an old wine barrel with five or six round 
holes in the bottom, placed on a circular boiler of cast iron or galvanized 
iron. The space between the boiler and the barrel is filled with a narrow 
sausage ring filled with sand to prevent escape of the steam except through 
the barrel. A fire is built in a pit beneath the boiler. Cross bars are 
placed in the bottom of the barrel to keep the clothes from the holes. 
When the steam is escaping too hot for the hand, the time required for 
delousing is one hour. The barrel is covered with a heavy wooden lid. 

3. A galvanized iron bin with water in bottom and a grid to keep 
the clothes from the water, placed over a fire, will serve for a small 
quantity of garments on the same principle as the barrel. An ordinary 
garbage can as used in the army will serve. 

4. In Egypt and Serbia, trains were fitted out and connected by 
steam pipes from the engine so that steam could be released in the cars 
through perforated tubes. The steam has exit through cracks about 
the doors, and reaches within the car a temperature about 105° C. 
(221° F.). The clothing is placed in bags or on shelves and may almost 
fill the car. Sterilization lasts one hour. 

b. Enclosed steam has been more commonly used and has likewise 
been the cause of most of the trouble. It may be applied either at normal 



THE CONTROL OF HUMAN LICE 



323 






or increased pressure, and in normal atmospheres or in vacuums (plate 
XXIII). Fulton and Stamford recommend the following procedure: 

1. Place woolen blankets or uniforms on hangers or loosely on trays 
in the sterilizer. 

2. Introduce 60 pounds steam into the outer jacket to prevent sub- 
sequent condensation within the sterilizing chamber. 

3. Create a 15 or 20-inch vacuum to facilitate penetration of the 
clothing by the steam. 

4. Sterilize with steam. 

a. No pounds (atmospheric pressure) for one hour. 

b. Twelve pounds steam for 10 minutes. 




Plate XXIII. — Steam sterilizer in delousing station of U. S. Army Medical Corps. 
The carriage is transferred along the rails in the foreground to rails leading into 
the other room where another carriage is seen. (Hutchison.) 



5. Produce 15 to 20-inch vacuum to facilitate drying. 

6. Open the door of the sterilizer about 4 inches for 10 minutes to 
allow gradual cooling of the contents of the sterilizer. 

Steam under pressure will disintegrate woolens if the exposure is pro- 
longed. The bacterial sterilization requires preliminary vacuum and 
loose packing. Garments placed in bags are likely to have the wrinkles 
set, if water of condensation settles in them when the steam has not pene- 
trated at a sufficiently high temperature. If the cooling or drying is 
very rapid, wrinkles and shrinkage are quite likely to result. 



324 SANITARY ENTOMOLOGY 



4. Hot Air D dousing 






Hot air was used very extensively for delousing the armies, especially 
on the eastern front. This system is not sterilizing, nor is it especially 
dangerous to the garments except when allowed to get too hot. Stagnant 
hot air has less effect than fresh hot air. The garments must be hung 
loosely. Provision should be made for circulating the air so that all of 
the clothes will receive the necessary amount of heat, which is 131° F. 
(55° C.) for 30 minutes, or 140° F. (60° C.) for 15 minutes. The heat 
chamber may be a portable box such as a fireless cooker; a room heated 
by steam pipes or hot air ; a sod hut ; a steel autoclave ; or an improvised 
oven. Very high heat must not be used on dry garments as it will dis- 
integrate the fibers of woolens and cause shrinkage. 

5. Fumigation 

When fumigation chambers are available and the clothing is needed for 
immediate wear, this is one of the quickest means of delousing. The 
fumigation chamber may be : 

a. A room, with cracks tightly sealed, and with vestibuled doors. 
A sign of warning should be posted and the door kept locked during fumi- 
gations. Only persons understanding fumigation should be permitted 
around, and they should wear gas masks. 

b. A chest or box is sufficient for carbon bisulphide or chlorpictin. 

c. A portable unit, such as an automobile with an air-tight chamber, 
and with hangers or shelves. The gas generator may be placed behind 
the chauffeur's seat. 

d. A vacuum chamber as in steam sterilization. The same cylinder 
may be made available for either steam or gas. 

The fumigation may be either at normal atmospheric pressure or 
in a vacuum. When a room is to be fumigated one should see that there 
are no persons in the building, as few buildings are constructed so that 
the gas can not penetrate to other rooms. 

To fumigate an entire building, or a room, close tightly all openings 
in building and seal up cracks with paper, unless the insects are in 
the double walls, in which case seal the cracks on the outside. It may 
be necessary, if the building is too loosely constructed, to increase dosages 
or make a tarpaulin to cover the entire structure. Such measures should 
only be taken in case the normal fumigation is unsuccessful. Any of 
the following methods are practicable. Entomologists prefer cyanide 
but many army officials prefer sulphur. 

a. Sulphur corrodes metal, so all movable metal should be taken out 
of the building. Sulphur fumigation is described in Public Health Bull. 



THE CONTROL OF HUMAN LICE 325 

34 (1910) with special reference to ships, and in Entomology Bull. 60 
(1906) with reference to general fumigation. 

1. Clayton gas is generated by burning common roll brimstone 
in an oven or generator outside of the building. A very high heat is 
generated. The gas is passed over two baffle plates before reaching 
the outlet pipe which is cooled by water circulating in pipes around 
it in an ordinary steam boiler tank. The gas then is passed into the 
building to be fumigated. This gas is a mixture of sulphur dioxide 
and sulphur trioxide. As the gas is heavier than air there must be 
circulation through the roof of a building or hatch of a ship until the 
gas begins to come out in quantity. 

2. Burn sulphur candles, being careful to isolate them by sufficient 
metal from all woodwork, at rate of 4 pounds per 1,000 cubic feet 
for 6 hours. 

b. Cyanide is one of the best known gases used for fumigation. 

1. Sodium cyanide only is now available. Generate in earthen 
jars, placing in the jar 1% oz. sulphuric acid and 2 oz. water to every 
ounce of cyanide to be used. Arrange the cyanide in a package sus- 
pended over the jar so that it can be released by the operator at a 
distance by pulling or releasing a cord. The gas is generated very 
rapidly and is exceedingly dangerous. Use 10 oz. of cyanide for each 
1,000 cubic feet and expose for 2 hours. This will kill all other insects 
present. 

2. Potassium cyanide should be used at the rate of 1 oz. cyanide 
to 1 oz. sulphuric acid, and 3 oz. of water. 

3. Chlorocyanogen (C1CN), in experimental work, gives promise 
of being fully as effective as HCN and much safer to use, because the 
irritation of the membranes of the nose and eyes gives warning of any 
leak long before sufficient gas has escaped to produce any toxic effect. 
The most practical method for fumigation of any kind would be a 

mobile motor fumigator with hose attachments capable of treating any 
building, tent, or car. If this unit had a tight fumigation room, gar- 
ments could be hung therein and practically fumigated. The installa- 
tion should be equipped with generators for cyanide, formaldel^de, or 
sulphur fumigation, and be placed in charge of practical fumigation 
experts. 

Vacuum fumigation has received several very successful trials. On the 
Mexican border it has been used by the Public Health Service, where 
a hydrocyanic acid gas fumigation is used. Many steam sterilizers now 
in use are available for gas fumigation. The following formulae have 
been tested and proven satisfactory: 

1. For chests, trunks, and tightly-packed garments 25-inch vacuum, 



326 SANITARY ENTOMOLOGY 

30 minutes exposure, 4 ounces sodium cyanide per 100 cubic feet 
(Lamson). 

2. For loosely-hung clothes, 20-inch vacuum, 30 minutes exposure, 
3 ounces cyanide per 100 cubic feet (Lamson). 

3. The hydrocyanic acid gas (DANGEROUS) is generated in an 
air-tight generator, which is connected by a pipe with the fumigation 
chamber, by combining 2% parts of sodium cyanide solution (made by 
dissolving 4 lbs. of sodium cyanide, guaranteed to contain 51 per cent, 
cyanogen, in 1 gallon of water), 1 part of commercial sulphuric acid 
(184 sp. gr., or 66° Baume) and 1 part of water. 

Create 25-inch vacuum. Generate gas 5 minutes in generator. Wash 
over into fumigation chamber. Break vacuum so as to fumigate in 
normal atmospheric pressure 25 minutes. Remove gas by producing 
25-inch vacuum. Return to normal pressure. Open door slightly and run 
vacuum pump a few minutes. Remove material. (Sasscer.) (See Fed. 
Hort. Bd., Service and Reg. Announcement 21, Dec. 4, 1915.) ONLY 
EXPERIENCED MEN CAN BE PERMITTED TO HANDLE. In 
case of asphyxiation from cyanide it is imperative to walk the patient 
up and down in the open air or to resort to artificial respiration. Few 
fatalities result under such treatment. 

For fumigation in boxes the following gases are available: 

a. Chlorpicrin in galvanized cans using 4 cc. to 1 cur ft. for 30 
minutes and applying a little heat. DANGEROUS GAS. (Moore.) 

b. Carbon bisulphide is an inflammable but efficient fumigant but 
too slow for most army purposes. Place garments in any kind of 
tight box and pour in the liquid at the rate of 1 lb. to 1000 cu. ft. 
of space. Leave for 24 hours. 

6. Storage 

Storage of infested garments, dry at 54°-68° F. (12°-20° C), for 
two or three weeks is effective. Bedding and clothing may be put away 
in naphthalene crystals or moth balls. 

7. Impromptu Delousing Arrangements 

Under temporary conditions none of the above-mentioned methods 
can be used to cleanse the garments and in such cases hot water washing 
or the use of other expedients is necessary. The outer clothing should 
be ironed and brushed at least once a week. 

A great number of remedies have been suggested and tried, but from 
these we may select a few which appear to be especially good. There 
probably will be times when one or another will be more practicable. 



THE CONTROL OF HUMAN LICE 327 

a. Boil clothes in water five minutes. 

b. Soak woolens in hot water at 131° F. (55° C.) 15 minutes. 

c. Soak clothes in insecticides. 

1. Immerse in benzole bath for 3 hours. 

2. Wash for 15 minutes in 10 per cent solution of one of the 
following soaps ; then wring out and dry. 

To obtain a 10 per cent solution dissolve 3 pounds in a 
bucket of water. The odor will be retained a long time and 
keep lice away. 

a. Naphtha soap 65% 
Cresol 35% 

b. Naphtha soap 65% 
100% crude carbolic acid 35% 

c. Naphtha soap 65% 
Xylol 35% 

3. Soak for 10 minutes in 2 per cent solution of cresol, wring 
out and dry. A quart of cresol in 12% gallons of water is enough 
to kill the lice in the body linen of 62 men, each garment being 
wrung out to recover as much as possible of the liquid. 

d. Handpicking, if done thoroughly and regularly, is often 
effective. 

e. Hot ironing if done well is effective. 

CONTROL OF LICE IN LIVING QUARTERS 

In addition to control of the lice on the man and his garments, it is 
necessary to control them in his lodgings, for the lice are quite likely to 
be scattered through bedding and clothing, especially in army quarters, 
and in lodging houses, and places where men subject to lice infestation 
are likely to congregate. 

The quarters should be treated as follows: 

1. Cleanse beds with gasoline or kerosene. Permit no fires. 

2. Send bedding and linen to laundry. 

3. Fumigate mattresses and pillows in fumigation chamber with 
cyanide as described for clothing; or, 

4. Fumigate the quarters as described above. 

When men are on active duty in war time, lice become very abundant 
in the trenches and dugouts. The men brush themselves off and the eggs 
and lice fall to the ground to reinfect other men. The following control 
measures will be of assistance : 

1. Spray walls with cresol or phenol solutions 2 to 5% strength. 

2. Scrape walls, sprinkle the dust with corrosive sublimate and 
remove. 



328 SANITARY ENTOMOLOGY 

3. When possible provide in dugouts a disinfecting kettle or box or 
barrel in which clothes can be treated with an insecticide as described 
under clothing. 

4. When possible, remove bedding and other comforts in which lice 
might lurk, to the rear, for disinfection. 

CONTROL OF LICE IN HOSPITALS 

When working in communities or camps where louse-borne diseases 
are common, it is imperative that the hospital attendants take every 
measure possible to prevent infection of themselves from patients and 
prevent spread of lice from patient to patient. The following recom- 
mendations are therefore of value in such cases. 

Control of Lice in Hospitals 

1. Moisten floors and walls with cresol or phenol. 

2. If possible patients should be washed before placing on clean beds. 

3. Attendants should wear clothes with few openings. 

4. Band legs of wooden beds with corrosive sublimate to prevent in- 
fection from other beds. 

5. Cleanse each bed before putting a new patient on it. 

6. Obtain free ventilation with fresh air. 

7. Have bedding disinfected for each case. 

Louse-Proof Garments for Medical Attendants, Etc. 

1. Smooth clothing, preferably rubber or oiled silk. 

2. Long coats, extending below the knee and buttoning behind. 

3. Sleeves narrow at the wrists. 

4. Rubber gloves drawn up to overlap edges of sleeves. 

5. Collars to button close around the neck. 

6. Head covered by a hood. 

7. Rubber or smooth leather top boots. 

8. A one-piece suit fastened at shoulders by buttons, with trousers 
closed at ends like stockings. Wear sandals over the feet. Rubber cap. 

9. Smooth capes are sometimes of value. 

10. Smooth silk underwear may afford a measure of protection. 

BIBLIOGRAPHY 

Boyd, Mark S., 1917.— Am. Journ. Pub. Health, vol. 7, No. 8, pp. 667- 

671. 
Brink, 1915. — Voyenno Med. J., Petrograd, vol. 264, Med. spec, pt., pp. 

440-449. 



THE CONTROL OF HUMAN LICE 329 

Fulton, Dudley', and Staniford, K. J., 1918. — Journ. Amer. Med. Assoc, 

vol. 71, No. 10, pp. 823-824. 
Hunter, William, 1918.— Brit. Med. Journ., Aug. 24, No. 3008, pp. 

198-201. 
Hutchison, R. H., and Pierce, W. Dwight, 1919.— Proc. Ent. Soc. Wash., 

vol. 21, No. 1, pp. 8-20. 
Moore, W., 1918a.— Journ. Lab. Clin. Med., vol. 3, No, 5, pp. 260-268. 
Moore, W., 1918b. — Journ. Amer. Med. Assoc, vol. 71, No. 7, pp. 

530-531. 
Nuttall, G. H. F., 1918.— Parasitology, vol. 10, No. 4, pp. 411-586. 
Pierce, C. C, 1917.— U. S. Public Health Reports, vol. 32, No. 12, pp. 

426-429. 
Pierce, W. D., Hutchison, R. H., and Moscowitz, A., 1919. — National 

Laundry Journal, Chicago, vol. 81, No. 1, pp. 4-14. 
Rulison, R. H., 1918.— New York State Journ. Med., vol. 18, No. 11, pp. 

443-451. 
Shipley, A. E.— Brit. Med. Journ. No. 2807, p. 679. 
Strong, R. P., 1915a. — Boston Med. and Surg. Journ., vol. 173, No. 7, 

pp. 259-262. 
Strong, R. P., 1915b.— Med. Rec, Nov. 20, p. 892. 
Wells, H. G., and Perkins, R. G.. 1918. — Journ. Amer. Med. Assoc, vol. 

70, No. 11, pp. 743-753. 



CHAPTER XXIII 

Lice Which Affect Domestic Animals 

Part 1. Cattle Lice and Their Control 1 
G. H. Lamson, Jr. 

Nearly every species of animal bearing hair or feathers is subject to 
the attack of from one to a dozen species of lice. A given species does 
not infest all kinds of animals, but is confined to certain related kinds. 

Lice are divided into two cardinal groups, according to their method 
of feeding. One order, the Mallophaga, includes biting lice like the 
bird lice and the small red lice on dairy animals, which feed on the dry 
skin, hair or feathers, but do not suck the blood. The other order, the 
Siphunculata, the sucking lice, fatten themselves by sucking the animal's 
blood. These of course are the most annoying, injurious, and dangerous. 
Some of the sucking lice, under certain conditions, may transmit fatal 
diseases, but none of the cattle lice are known to do this. The present 
lecture deals only with the species which infest dairy and beef cattle. 

The place where stock is kept has a part in the degree of infestation, 
for cows that are placed near other badly infested cows have a greater 
opportunity for becoming lousy than those that are stabled with cattle 
that are comparatively free from lice. Where lice have occurred year 
after year, there is a greater danger of infestation than where the stables 
have been kept clean, well ventilated, and well lighted. The lice cannot 
maintain life for any extended period of time away from the cows. If 
the stables are kept clean, well lighted, and ventilated there is somewhat 
less danger of infestation. 

Too much stress, however, has been placed upon the condition of 
bedding and stables and not enough upon the condition of the stock, for 
it is doubtful if any cow is ever entirely free from lice for the whole year, 
even where the stables are kept scrupulously clean and well managed. 
Careful examination of the infested herd will show that there is con- 
siderable difference in the number of lice on different cows ; some are very 

1 This lecture was presented November 11, 1918. It is based primarily upon condi- 
tions in dairy herds, and therefore all of the recommendations may not be applicable 
to range conditions. — W. D. Pierce. 

330 



LICE WHICH AFFECT DOMESTIC ANIMALS 331 

badly infested early in the winter, some will have a few lice on them, and 
others will seem to be free from them. 

The degree of dryness of the skin is often closely related to the num- 
bers of lice on the different cows. When cows are not in good physical 
condition this results in a lack of natural oiliness of skin and makes con- 
ditions ideal for lice to increase. It will be noted that the variation in 
the numbers of lice on cows varies with the breed; that Holsteins are 
notably among the most infested; that Ayrshires and Guernseys are 
intermediate; and that Jerseys are not so badly infested. Calves, which 
have less oily skin than older stock, are more generally infested with lice. 

There is a marked difference in the season of the year when lice are 
more numerous. The skin secretions are reduced in the winter and it is 
then that the lice are most numerous. In the summer only a few can 
be found. Certain cows in a herd will be infested early and will continue 
infested through the winter. The fact that Holsteins, being usually 
either black and white, or having the combined markings, make the lice 
more conspicuous, seemed at first to offer a solution for the reason 
why they have been generally conceded to be the most heavily infested 
breed of cows. Considerable study has, however, borne out the fact 
that this greater susceptibility is due to the general lack of skin secre- 
tion of the breed. For these reasons, it is believed that not only should 
we try to keep the stables clean, well lighted, and well ventilated, but 
also keep the stock in good physical condition. The fact that the lack 
of oiliness of skin tends toward lousiness indicates a logical control meas- 
ure for these parasites. 

Cattle lice are by no means uniformly distributed over a cow, particu- 
larly if they are of the sucking species. The upper portions of the neck, 
shoulder tops or withers, escutcheon and the switch of the tail are usually 
the parts that are infested with the largest numbers. 

The forehead, portions between the horns, and the throat are places 
where the lice are next most likely to be found. It is these places, espe- 
cially the upper portions of the neck and withers, that the dairymen 
should watch for indications of their presence and it is to these places 
that the insecticide or control measure should be applied most liberally 
and most thoroughly. While the small red biting lice move about some- 
what, the sucking lice remain stationary during the greater portion of the 
time before reaching maturity, feeding continually. 



SUCKING LICE 

The short-nosed cattle louse, Haematopinus eurysternus Nitzsch, is 
the best known of the cattle lice. It is very broad and measures in the 



332 SANITARY ENTOMOLOGY 

female about one-eighth to one-fifth of an inch, while the males are a 
little smaller and a little narrower. 

The eggs or nits are white and can be distinctly seen glued tightly to 
the hairs along the shoulders. From thirty-five to fifty eggs are laid by 
the mature females and these are laid a few each day. The egg-laying 
period may extend over a period of ten to fifteen days. These eggs 
hatch in from seven to eight days and the young lice commence draw- 
ing the cow's blood near the point where they were hatched. The rate 
of growth depends somewhat upon the blood supply in the portion of 
skin where they work. They mature in from fifteen to eighteen days, 
when the females in turn lay eggs. 

The long-nosed cattle louse, Haematopinus vituli Linnaeus, is often 
spoken of as the "blue louse," or the louse attacking calves, though it 
occurs frequently on older stock. It is distinguished by being darker in 
color and slender in shape with a long pointed head. When seen on the 
cattle it seems to be literally standing on its head with mouth-parts buried 
in the skin, feeding on the blood of the animal that it infests. It is 
found more commonly on the neck and shoulders of the animal. 

The mature insects are a dark bluish gray in color, giving them an 
appearance of being either blue or black, and they are about one-eighth 
of an inch long. Their color and their small size allow them to pass 
unnoticed especially on stock of a darker color. If one will turn back 
the hair until the skin of the animal can be seen, their presence may be 
made out by the shining surfaces of the abdomen. If they can be made 
out on the calves having white markings, they can usually be assumed to 
be present on the others, and there should at least be a close observation 
of all the calves. 

The eggs of this louse are dark, nearly black, and hatch in from 
eight to nine days. Like the previously mentioned species, these lice 
move about but little before maturity, but continue feeding near the 
point where they were hatched. They in turn lay eggs in fifteen to 
eighteen days. 

BITING LICE 

The little red cattle louse, Trichodectes scalaris Nitzsch, is perhaps 
the most generally found on cattle. It seems to be out of place as it is 
of the biting group, and this group is most commonly found on birds. It 
feeds on the hair and loose scales of the skin, and the drier the skin of the 
cow, the more numerous these lice become, until they can be made out by 
the thousand, closely matted in the hair. They are most commonly 
found on the neck and shoulders, though in bad cases they are found 
pretty generally over most parts of the animal. Unlike the two previ- 



LICE WHICH AFFECT DOMESTIC ANIMALS 333 

ously mentioned species, they move about considerably among the hairs, 
having feet well adapted for this purpose. 

These lice are small, yet visible with the naked eye, measuring about 
one-thirteenth of an inch. They are reddish in color, having distinct 
bands across the abdomen. The general shape of the body is quite dif- 
ferent from that of the sucking lice, for their heads are broad and blunt, 
while those of the sucking lice are much more pointed. 

The problem of working out the life history of these lice was much 
more difficult, and the length of time during the various stages could 
not be worked out with the degree of accuracy that was possible with 
the less active sucking species. 

The eggs hatch in from five to seven days. The period from hatching 
until the lice are mature and eggs are laid again, is about fourteen days. 
The eggs are delicate white, flask-shaped forms, having a small cap or 
lid on one end that is removed when the egg hatches, while the other end 
is firmly glued to the hair. 

It was found more difficult to exterminate these small red lice either 
with sprays, oils or fumigations than it was to kill the larger sucking 
lice. This was possibly due to their more resistant chitinous covering, 
their large numbers and their activity. 

METHODS OF STUDY OF EIFE HISTORIES 

Much time was taken to determine the periods of incubation of the 
eggs of different species of the cattle lice and the length of time necessary 
for the lice to mature, because this was considered an important feature 
that would determine the proper length of time between applications of 
control measures. It would be difficult to find any substance active 
enough to kill the embryo louse in the egg, thus preventing it from 
hatching, and at the same time not be so active as to do injury to the 
skin of the cow. The control must therefore be based on some other phase 
of the life cycle. 

In order to make sure of no previous infestation, the method was to 
isolate a new-born calf and place adult female lice that had been fer- 
tilized upon the shoulders of the calf and watch for the first presence of 
eggs. As a rule these were found a few days after the lice were placed 
on the calf. Eggs were examined each day and as many of the old lice 
as could be found were removed from the animal. It was surprising 
how many of the sucking lice could be found after they had been placed 
on the shoulders of the calf, for they moved but little from where they 
were first placed. The calf was thrown on a bundle of hay each day at 
the same hour and the caps on the eggs were watched. Where these were 
found removed, the period of incubation was recorded. 



334 SANITARY ENTOMOLOGY 

After the young had developed for several days and were sufficiently 
large to handle readily, they were placed upon the escutcheon of a cow 
that had been inspected thoroughly and found free from lice. Other lice 
were left on the calf. In a given number of days eggs could be found 
on both the calf and on the escutcheon of the cow. These eggs were 
again watched until they hatched and in this way the periods of time 
were recorded, and checked often enough to be reasonably sure of the 
accuracy of the results. 

With the biting lice the work was much more difficult because these 
do not remain in one place. Celluloid caps, somewhat like those used for 
protecting vaccination points, were used to confine the lice. Areas were 
shaved leaving small tufts of hair on which the lice could breed, and 
adhesive tape bound the caps to the calf. The electric incubator kept at 
the approximate temperature of the cow's skin was used to supplement 
the observations made on the animal itself. 



CONTROL MEASURES 

A control measure or remedy for cattle lice, in order to be practical, 
must be cheap, reasonably easy to apply, effective in killing the lice, and 
at the same time do no injury to the cow. It should not be so poisonous 
that the accidental consumption by animals would endanger their life. 
At the same time the material used for control should be commonly sold, 
and thus be within the reach of purchasers even in the remoter country 
villages. 

Clipping. — Clipping the stock over the portion of the animal most 
likely to be infested is not an uncommon practice, and, where the hair 
is long and the animal is very badly infested, it helps to bring the oil 
or wash where it will be most effective. We have found, however, that 
animals that have been clipped are more liable to show a considerable 
scurfing of the skin because the application reaches the skin more quickly 
and in larger quantities than when it is held on the hair and thus reaches 
the skin gradually. There are those who feel that the animals do not 
look as well when clipped. 

If control measures are used early, thoroughly, and repeated through- 
out the winter, clipping will be unnecessary. 



OILS 

Raw Lmseed Oil. — Of the many different measures for the control of 
lice on dairy cows and young stock, raw linseed oil gave the best results 
from the standpoint of economy of material and labor of application, 
killing the lice, but not injuring the skin, and at the same time not 



LICE WHICH AFFECT DOMESTIC ANIMALS 335 

making it necessary to thoroughly drench the cow. It has no poisonous 
properties. It is a logical remedy, since the lack of oiliness in the 
skin of the cow is a fundamental reason for her being lous} 7 . Linseed 
oil can be put on at the time of grooming or cleaning the cows, thus 
doing two things in one application. From four to five cows can be 
treated with a pint. 

Raw linseed oil can be best applied with a brush having bristles of 
unequal length, of which the rice fibre brushes are probably most durable. 
When applied with a sponge, the shedding hairs become matted on the 
sponge, making application a little more difficult. 

It takes about five minutes to apply linseed oil to the cow's coat 
and a slight oiliness will remain for several days, which is a desirable 
feature. On some animals the loose skin may scurf or lift, giving one 
the impression that some little irritation has been caused. But if one will 
give the condition study, he will see that there has been no inflammation 
or reddening of the tissues, but that the loose epidermis has lifted. 

The use of raw linseed oil as a control for cattle lice is neither new 
nor patent. It has been used by scores of dairymen in the past with 
good results. Some have used it once and expected that application 
should last for the whole year and have been anxious to get some one 
treatment that would do for all the time. A few others have possibly 
noticed a slight scurfing of the skin on some animal and have decided that 
it was burned by the application. If, however, raw linseed oil is applied 
in the right manner and repeated at necessary intervals, it will be 
found to be one of the most effective agencies for the control of cattle 
lice, and will save time, labor, and injury to the animals. 

The use of boiled linseed oil is not recommended as there is some 
little danger of burns in using it, particularly if it is rubbed forcibly 
into the skin. 

To avoid any danger of raw linseed oil scurfing or burning the skin 
observe the following directions. Do not rub the skin too vigorously 
when applying the oil. Do not allow the animals that have been treated to 
go out in the strong sunlight until at least twelve hours after applying the 
oil. Do not exercise the animal after the treatment. Do not cover the 
cow. Do not use the boiled or refined linseed oil. 

Linseed oil is used internally for other purposes and is a safe 
remedy if properly applied. 

SPRAYS 

Many dairymen practice spraying cows and some have obtained 
good results from using spray materials such as creolin, kerosene emul- 
sion, tobacco solution, and arsenical washes. A small bucket pump an- 



336 SANITARY ENTOMOLOGY 

swers for this spraying. Thoroughness is essential and it is sometimes 
necessary for two or three to work on the same animal at the same time 
brushing the spray material into the hair before it runs off. 

Some dairymen do not take measures against the lice on their cows 
because they feel that spraying is the only method that will reach 
these insects, and that the danger from the animals catching cold after 
such a treatment more than offsets the injury of the lice. There is but 
little danger of cows catching cold if they are in good health, particu- 
larly if the day is not too cold, and if the cows are covered well after 
the treatment. 

Our trials indicate that the average spraying material such as creo- 
lin, kerosene emulsion, or an arsenical wash, together with the labor fac- 
tor, costs about ten cents per animal for each treatment. 

There are disadvantages in this treatment, including the labor and 
time factors : the amount of equipment necessary ; and the fact that a 
number of these sprays are not effective enough to kill the lice, or they 
are too strong for the cow's skin, or their effectiveness does not last for 
any considerable time after the application. The most important of 
these control measures are listed and their advantages and disadvantages 
mentioned. 

Creolin. — Of the materials used for spraying cows a solution of creo- 
lin is one of the most common. The strength should not be less than four 
per cent to kill the lice, and not more than five per cent, as this will cause 
some scurfing. A four and one-half per cent solution will give the best 
results for creolin. 

Kerosene Emulsion. — This emulsion has been used with satisfactory 
results by some dairymen. It is made by shaving one-half pound of 
laundry soap in one gallon of soft water that has previously been 
brought to the boiling point. When the soap is all dissolved, remove 
from the fire and add two gallons of kerosene oil. Stir this thoroughly, 
and if you have a bucket pump, place this in the mixture, turning the 
nozzle back into the bucket so the material is constantly passing through 
the pump. This will form a cream emulsion. If any free oil separates 
from this mixture continue pumping until the oil ceases to show. Then 
mix this amount with twenty gallons of water and apply either with a 
spray pump or with a brush, preferably the former. In using kerosene 
emulsion we have observed that the lice were not killed with a mixture 
that was so weak that it would not do injury to the skin of the 
animals to which it was applied. For this reason the linseed oil gives much 
better results. 

Arsenical Washes. — Arsenical washes are also used for the control of 
cattle lice, but owing to the great care necessary in using them, both from 
the danger of poisoning and the possible injury that may occur by using 



LICE WHICH AFFECT DOMESTIC ANIMALS 337 

them too strong or in applying them too vigorously, it has been felt that 
less dangerous applications can be made with even better results. 

One thing can be said for them, however, and that is regarding their 
effectiveness. That the lice are killed by the application of arsenical 
washes there is no doubt. 

One formula recommended is as follows : 

% lb. caustic soda (85% pure). 

% lb. white arsenic (99% pure) fine powder. 

% lb. sal soda. 

1/2 pt. pine tar. 

30 gallons water. 

In preparing and using any arsenical dip or wash one should re- 
member that arsenic is a poison and take precaution to avoid injury. 
If animals are allowed to drain where they may drink the solution, or 
feed when the solution is dripping off of them, they are liable to be 
poisoned. 

Care should be taken too that the hands should not be exposed any 
more than necessary. 

The arsenical washes may be necessary to use for dips for large 
herds and under range conditions, where tick infestations also occur, but 
their use is questioned for smaller tick-free herds. 

For fuller information regarding arsenical dips and washes for cattle 
on range see Farmers' Bulletins Nos. 608 and 909. 

Nicotin washes.— These are questionable owing to the fact that ex- 
treme care must be taken in order to keep the wash away from the cows 
so that they will not get some of it internally. Cows are particularly 
susceptible to poisoning from tobacco decoctions. 

MISCELLANEOUS REMEDIES 

Greases. — Mercurial ointment is one of the most effective of lice 
killers though it is very liable to cause burns even when it is diluted con- 
siderably. This ointment diluted with twelve parts of vaseline was used 
on some cows and burns resulted from the application. 

Kerosene Oil and Lard have been used considerably for cattle lice 
but the danger of injury to the skin with the use of kerosene oil, unless 
Very thoroughly mixed with some diluent, is alwa}^s present. 

With the majority of the greases, the inability to spread properly 
makes their application expensive because of the quantities of material 
required to cover the regions infested by lice. 

Powders. — Dusting powders are usually sulphur, naphthalene, and 



338 SANITARY ENTOMOLOGY 

pyrethrum. These are not recommended. Cattle lice are too difficult to 
control for such methods to be effective. 



TIME FOR THE APPLICATION OF CONTROL MEASURES 

Though cows are infested with the largest numbers of cattle lice 
during the months of January and February, yet the measures for their 
control should be applied long before that time ; in fact, they should be 
used within a week after they have been brought into the barn for the 
fall and winter. A second application should follow twelve or thirteen 
days afterward. The purpose of these two applications is to rid the 
cows of the lice that are on them before they become numerous and 
spread to more susceptible animals. The lice may not be seen at this 
time but the dairymen should not reason that the lice are not present. 
This gives a proper length of time for all of the three species of cattle lice 
to hatch from eggs, but not long enough for them to lay eggs again and be 
in a resistant stage where the treatment will not reach them. 

Treatment should be repeated at intervals of a month from the 
second treatment. In case animals show any great number of lice, 
treatment should be given and repeated in twelve or thirteen days. 

Treatment with linseed oil can be made at the usual time when the 
cows are being groomed and cleaned. 

From five to six treatments during the fall and winter should control 
the lice in the average herd. 

SKIN INJURIES 

One of the most troublesome phases of the study of the control of 
cattle lice was to determine the strength of insecticides that would kill 
the lice but would not injure the skin, thus causing the hair to come out 
badly or making distinct burns. 

The skin of the cow is very susceptible to injury when compared 
with the skin of other animals. It is known that cows have been killed by 
the application of certain insecticides recommended for the control of 
cattle lice. This indicates that caution must be taken in the use of control 
measures that have not been sufficiently tested. Caustic washes cannot 
be used without danger of their doing considerable injury, unless they 
are very accurately measured and applied very carefully to the skin of 
the animal. 

It is known that exposure to direct sunlight and active exercise after 
application contributes to cause skin injury with nearly every one of the 
control measures for cattle lice. 

It is doubtful if there is any application that will kill lice on cows 



LICE WHICH AFFECT DOMESTIC ANIMALS 339 

that will not cause a slight degree of scurfiness on the cows at times. If 
one will look at a condition of scurfiness carefully he will find that loose 
portions of the epidermis have lifted, and fragments are thick in the 
hairs, yet there is no irritation or reddening of the tissues and hence no 
real injury. Scurfiness is a condition that may occur without an}' appli- 
cation to the skin and it should not deter the dairyman from using a con- 
trol measure that does not cause a real injury. Scurfiness passes in a 
short time and leaves the skin clean underneath. 



Part 2. Lice Affecting Chickens, Hogs, Goats, Sheep, Horses, and 

Other Animals 

F. C. Bishopp 

The habits and control of lice on cattle have been discussed in another 
lecture. Owing to the marked economic importance of lice on other 
animals, the diversity of their habits and the great difference in the 
methods of handling the hosts, an additional lecture is devoted to the 
subject. 

LICE INFESTING DOMESTIC FOWLS 

Fowls are infested with biting lice (order Mallophaga) only. There 
are a large number of species living on the various domestic fowls. The 
chicken is infested with about ten species (seven of these commonly), the 
turkey with four, the pigeon with eight (three commonly), the duck five, 
the goose seven, the guinea fowl six, and the peafowl four. 

Of course in listing the number of lice on the different hosts enumer- 
ated there is some duplication. We find that under certain conditions 
chicken lice are to be found on several of the other domestic fowls and 
this is true to some extent with forms which are found on other species. 
There are a number of factors which influence the transference of any 
of these parasites from their normal hosts. Ordinarily most of them 
are quite closely restricted to one species of fowl and the habits of the 
louse and the host are so interrelated that it is doubtful if many of 
them will continue to breed successfully on strange hosts, although of 
course they may be harbored for a time. When several species of fowls 
are closely associated, especially on roosts, there is a considerable chance 
for the interchange of the different species of parasites and we can not 
always say that when a given species is found on an unusual host it 
will succeed in establishing itself and breeding thereon. Furthermore we 
have observed that the young of a species seems to be attacked by a 
smaller number of species than the adult fowls. In fact some of the 
species of lice most commonly found on adults do not seem capable of 



340 SANITARY ENTOMOLOGY 

breeding on the young. This has been observed in the shaft louse of 
chickens. On the other hand some of the species, for instance the head 
louse of chickens, appear to thrive better on the young than on the 
adults. 

Life Histories. — Very few of the so-called bird lice have been studied 
fully. Our lack of knowledge of the life histories and habits of these 
parasites is partly due to the difficulty of successfully rearing them 
under control. There is a marked difference in the habits of the differ- 
ent species of lice occurring on the same host. This may be explained by 
the fact that the parasite has become modified in structure and function 
of body parts to live under certain restricted conditions. For instance, 
on the chicken we find the head louse breeding largely on the head of 
chickens and seldom occurring on other parts. This species hangs to 
the down on young chickens and is usually found closely adhering to the 
base of the feathers on the heads of grown fowls. The body louse on the 
other hand has adapted itself to living on the skin of the host and 
is not commonly found on the feathers. This species is very active and 
depends for protection on its agility on the comparatively bare parts of 
the skin. The shaft louse usually rests along the shaft of the feathers 
but can run freely on the skin, going from one feather to another. The 
wing louse is ordinarily found between the barbules on the larger wing 
and tail feathers, and the fluff louse, a very awkward and sluggish species, 
clings to the fluffy parts of the feathers, principally on the thighs and 
sides. 

The eggs of the different lice are laid in the regions where the lice 
are usually found. The head lice eggs are attached singly to the 
feathers on the head and neck. The body lice attach their eggs to the 
base of feathers and are usually found in masses, especially on the base 
of the feathers below the vent where sometimes the masses become ex- 
ceedingly large — nearly half an inch in diameter. 

The life histories of a few of the common species have been worked 
out by Mr. H. P. Wood and the writer. The head louse will serve as an 
example. The eggs of this species hatch in from four to five days into 
minute pale rather active larvae and these after molting their skins sev- 
eral times become adults in from 17 to 20 days, and egg laying begins a 
few days later. As far as we have observed, the length of the developmen- 
tal period of the different species is quite similar. 

It is difficult to get any accurate record of the longevity of lice on the 
host but we believe they live for several weeks if not months. When re- 
moved from the host the longevity is comparatively short and this of 
course assists in the application of control measures. The body lice 
usually die within a few hours, while the head and wing lice are more 
persistent. Professor Theobald records keeping the shaft louse alive for 



LICE WHICH AFFECT DOMESTIC ANIMALS 341 

nine months apart from the host. This seems exceptional as we have 
never observed longevity to exceed three weeks. While specimens of lice 
may drop off with feathers, we find in the method of treatment which is 
described below that no concern need be felt for the reinfestation of a 
flock from this source. It also appears that wild birds play very little 
part in the carrying of these pests. Of course it is possible that sparrows 
or other birds intimately associated with domestic fowls might accident- 
ally carry a few specimens from one yard to another. 

Injury and Losses. — It is difficult to weigh the loss produced by lice. 
It is generally believed by poultrymen that where they are at all abundant 
they materially affect the development and egg production in fowls. Cer- 
tain it is that young chicks are frequently killed by the attack of the head 
louse and this also applies to } 7 oung turkeys and ducks. Just how the 
injury is produced is still a matter of debate. Since the lice do not suck 
blood it is generally believed that the injurious effects are produced by 
the irritation caused by the gnawing and running about of the parasites. 
We have seen repeated instances of the rapid increase in weight of grown 
fowls after they have been freed of lice and experiments now under way 
seem to indicate clearly that egg production is markedly affected by even 
moderate infestations of lice. In addition to these adverse effects it has 
also been found that lice, especially when present in numbers, mutilate 
the plumage of the fowls. This is of special importance in show 
birds. 

While no disease has been demonstrated to be carried by poultry 
lice, it is not improbable that they may play a part in the transmission 
of some maladies of fowls. They have been suspected of being concerned 
in the spread of the so-called chicken pox, or sore head, and favus. 

Methods of Control. — While there are a number of insecticides which 
are fairly satisfactory in reducing the number of lice on poultry, experi- 
ments carried out by Mr. H. P. Wood and the writer at Dallas, Texas, 
indicate that none of them are as satisfactory as sodium fluoride. The 
commercial grade ranging from 90 to 97 per cent NaF is used. This is 
a white powder readily soluble in water and with comparatively low toxic 
effect on the higher animals. It has been found that one light applica- 
tion is sufficient to completely rid a fowl of all species of lice. The action 
of the material is rather slow, especially when it is used in the dust 
form. Usually it takes about four days for all lice to disappear 
from the feathers. Since the lice chew their food and since other para- 
sites which suck the blood from the host are not destroyed to a large 
extent, it is believed that the material acts largely as a stomach poison. 
Hatching of the eggs does not appear to be prevented but the } T oung lice 
succumb very soon after emerging from their shells. 

Sodium fluoride may be applied either as a powder or in solution. 



342 SANITARY ENTOMOLOGY 

When comparatively few fowls are to be treated or if chicks or un- 
healthy individuals are concerned, it is advisable to follow what we term 
the pinch method of application. For grown fowls about twelve pinches 
of the powder are placed on different regions of the bird at the base of 
the feathers and distributed as follows: One pinch on the head, one on 
the neck, one on the throat, two on the back, one on the breast, one 
below the vent, one on the tail, one on either thigh, and one scattered on 
the under side of each wing when spread. With young chickens usually 
one pinch is sufficient, this being distributed on the head, neck, along 
the throat and on the back. A few people have reported loss of young 
chicks through the application of the powder to them at night. We are 
therefore recommending that the treatment be done during the early part 
of the day while the chicks are active. This gives opportunity for excess 
dust to be shaken off before roosting time. Another precaution is to 
apply the treatment where the dust will not have opportunity to get into 
the food or water. As the dust is very irritating to the nose and throat 
it is advisable to wear a dust guard or a moistened cloth tied over the nose 
and mouth when applying it. 

By the dry method one pound is sufficient to treat 100 grown fowls 
and they can be gone over at the rate of about one to every two or three 
minutes, with one man working. 

In following the dipping method, the sodium fluoride is dissolved 
in water at the rate of one ounce or three level tablespoons to each gallon. 
A tub is well filled with this solution which should be tepid (70° to 80° F.) 
but not warm, and the fowl, held by grasping the base of the wings 
over the back, is lowered quickly into the water. With the other hand 
the feathers are ruffled so as to allow the liquid to penetrate to the skin. 
The head is then ducked, lightly rubbed to induce penetration and the 
fowl released. By this method the danger of not treating all portions 
of a fowl is practically eliminated, the time of treatment is reduced to 
about three-fourths minute per fowl and the amount of material also 
markedly reduced. The irritating effect of the dust on the operator is 
also avoided. 

It is of course necessary to cnose a warm day so that the feathers 
will dry quickly. It should be stated, however, that the plumage is not 
thoroughly wet as would be the case with most dips. The feathers be- 
come completely dry in a couple of hours. There is absolutely no stain- 
ing or injury to the feathers, no tainting of flesh and no skin irritation 
produced either by the dipping or dusting methods. As the material is 
corrosive it is inadvisable for one doing the dipping to subject lesions on 
the hands to the liquid and the utensils used should be emptied imme- 
diately after completing the work. 

Since one application will completely destroy all forms of lice on a 



LICE WHICH AFFECT DOMESTIC ANIMALS 343 

fowl, there is absolutely no reason why lice should not be completely eradi- 
cated from a flock. Of course to accomplish this every bird must be 
treated at about the same time. All that is necessary to maintain a 
louse-free condition is not to allow infested fowls to come in contact with 
the clean flock. 

It has been found that a thorough application of flowers of sulphur 
will destroy all lice, but since a much larger amount is necessary the 
expense of treatment is greater than when sodium fluoride is used and 
there are also said to be some deleterious effects from the free use of 
sulphur although this has not been observed by the writer. Mercurial 
ointment or blue ointment is extensively used against lice. If applied as 
generally recommended it will not accomplish the complete destruction of 
the lice present and repeated applications are necessary to .keep them 
in check, which would be expensive. There is also some danger of pro- 
ducing mercurial poisoning by the free use of this material. The so- 
called "Cornell Powder," consisting of a mixture of carbolic acid, gaso- 
line and plaster of Paris, is quite effective, but as the eggs of the lice are 
not destroyed two or more applications are necessary to accomplish what 
can be done with one application of sodium fluoride and the trouble of 
mixing the material is considerable. 

For the treatment of pigeons it is advisable to dip them individually 
in sodium fluoride solution made as above described but with the addition 
of one ounce of laundry soap to each gallon of water in order to increase 
the wetting power. The squabs must also be treated. 

Turkeys may be treated precisely as are chickens, either by the pinch 
or dipping methods. The large birds should receive about eighteen 
pinches of powder and of course a large tub is necessary for proper 
dipping. 

It is recommended for exterminating lice from a flock, that the treat- 
ment be given if convenient in the late summer after the young chickens 
have matured and the flock has been culled and reduced to a minimum. 
Of course if lice are present there is no objection to treating at any time 
during the year and the quicker the treatment can be given the better. 
As poultrymen generally recommend hatching of chicks early in the 
spring this tends to reduce the loss from lice and other poultry parasites, 
but of course this should not be depended upon when so simple a method 
as the sodium fluoride treatment is available. 



LICE INFESTING RABBITS, CATS AND DOGS 

Domestic rabbits are not infrequently infested with an elongate, blue 
sucking louse. They seem occasionally to become sufficiently numerous, 
especially on young rabbits, to retard growth and reduce vitality. The 



344 SANITARY ENTOMOLOGY 

writer knows of no experiments which have been carried out with the 
control of this species. No doubt care would have to be exercised irr. 
choosing insecticides to apply to rabbits. 

Cat lice are comparatively uncommon. A few cases of infestations of 
cats with sucking lice have been observed by agents of the Bureau, but 
the species concerned has not been determined. The biting louse, 
Trichodectes subrostratus Nitzsch, seems more common and occasionally 
cats which have not received proper care are heavily infested. 

Complete freedom from the biting lice should be secured by a light 
but general application of sodium fluoride to the host. Dips contain- 
ing phenols should be used guardedly, as cats are sensitive to their 
action. 

Dogs are occasionally observed heavily infested with the sucking 
louse, Haematopinus piliferus Burmeister. The biting louse, Trichodectes 
latus Nitzsch, is far more common than the sucking form and it is espe- 
cially annoying to puppies. This parasite has been found to yield readily 
to a single application of sodium fluoride in the dust form. When sucking 
lice are present two dippings in kerosene emulsion or in one of the stand- 
ard coal tar dips should be given at ten-day intervals. 

THE HOG LOUSE 

Throughout the entire United States and in fact throughout the 
greater portion of the world hogs are infested with a large and repulsive 
appearing louse with sucking mouth-parts. The species is known scien- 
tifically as Haematopinus suis Linnaeus. This parasite assumes its 
greatest importance in the warmer portions of the country and is espe- 
cially injurious to hogs which are poorly fed or kept in insanitary 
crowded pens. 

Although the species may live for a few days (about five) apart from 
the host we need consider only the treatment of the host in controlling 
it. Of course it is well to remove hogs from the pens where they have 
been kept for five or six da} ? s after each treatment. The eggs are laid 
on the hair, especially behind the shoulders, in the flanks along the belly, 
and behind the ears. They hatch in about thirteen to twenty da}'s, ac- 
cording to Watts, the lice mature in about ten to twelve days, and the 
first eggs are deposited a day or two later. 

Little need be said here regarding the injurious effect of the louse. 
It is generally accepted as an important retarding factor in hog raising. 
Where it is allowed to multiply uncontrolled the skin becomes inflamed, 
scabby and thickened and the animals present an unthrifty appearance, 
growth is retarded and fattening is practically impossible. It has been 
held by a number of authors that the species may play a part in the 



LICE WHICH AFFECT DOMESTIC ANIMALS 345 

transmission of different diseases of hogs including cholera, although 
thev are now generally believed to be of little importance in this connec- 
tion. 

Control Measures. — For the breeder of hogs in considerable numbers 
there is undoubtedly no better method for controlling hog lice than 
through the use of the dipping vat. A number of insecticides have been 
found effective against them, including crude petroleum (two inches float- 
ing on water in the vat), kerosene emulsion, and many of the standard 
coal tar dips. It is important to get the hogs completely under the dip. 
In order to insure complete destruction of the species it is necessary to 
repeat the dipping a second time after a lapse of ten days. 

For the small raisers the expense of installing a vat is unnecessary as 
the application of any effective material with a spray pump or by hand 
with a brush is satisfactory. The concrete hog wallow containing water 
on which is floated a film of crude petroleum is fairly satisfactory, al- 
though if these wallows are not properly kept they may be objectionable 
from a sanitary point of view. Others use various types of hog oilers by 
which the oil is applied to the animals as they rub against the appliance. 
Still others simply sprinkle the oil on the backs of the hogs from a water- 
ing pot. Other insecticides are sometimes applied in the same way. 
Many oils, including kerosene oil, seem to be quite effective. 

The application of insecticides by the use of wallows, hog oilers, sprin- 
kling cans and similar methods can not be relied upon to destro}' all lice 
but will give a moderate degree of control if repeatedly attended to. 

To avoid burning the hogs, or other injurious effects, they should 
be treated towards evening or on cloudy days and should not be over- 
heated either before or after applications. 

It has been observed that hogs fed on garbage are comparatively 
or entirely free of lice. This condition is undoubtedly the result of con- 
tinual application of grease by the wallowing of the hogs in the gar- 
bage. 

EICE ATTACKING SHEEP 

The lice infesting sheep seldom become so abundant as to be consid- 
ered of much importance. The so-called foot louse, Linognathus pedalis 
Osborn, a suctorial species, was found by Osborn at Ames, Iowa, on sheep 
imported from Canada. It was present only on a comparatively few of 
the sheep. Evidently the species is not at all common in the United 
States. It occurs, so far as known, only on the legs, especially in the 
region of the dew claws and not on the heavy wool-parts of the host. This 
immediately suggests the use of a shallow wade vat by which a good 
delousing agent might be applied without coming in contact with the 
wool on the body of the host. 



346 SANITARY ENTOMOLOGY 

The biting louse, Trichodectes sphaerocephalus Nitzsch, of sheep is 
much more frequently met with than the sucking species and has been 
taken in various parts of the United States. It never seems to become 
abundant on the heavily wooled breeds. 

It has been reported that the thin wooled sheep raised by the Indian 
tribes in northern New Mexico and Arizona are often heavily infested with 
lice. Undoubtedly there is a close correlation between the character and 
amount of wool and the reproduction of lice on the host. 

Sodium fluoride may be successfully employed against the biting louse 
but on account of the close covering of wool the application must be 
thorough. The same method of application as suggested for the biting 
lice of goats should be used. Of course where sheep are dipped for the 
sheep tick (Melophagus ovinus), or scabies, the lice will be kept under 
control. Nicotine sulphate or lime-sulphur arsenic dip seem very effective 
against both the lice and the sheep tick. The former should contain about 
0.07 per cent of nicotine sulphate. The latter consists of a lime-sulphur 
dip of the formula : 8 pounds unslacked lime, 24 pounds flowers of sulphur, 
and water to make 100 gallons. Take 150 gallons of this concentrate 
and 350 gallons of warm water and add a concentrated arsenical solution 
containing 12 gallons water, 12 pounds sal soda and 4 pounds white 
arsenic. 

BITING AND SUCKING LICE OF GOATS 

Goats of all breeds are subject to the attack of lice but this tendency 
seems especially marked among the angoras. The biting lice consisting 
of two species, Trichodectes climax Nitzsch and T. hermsi Kellogg and 
Nakayama, are the principal species. The former of these is the pre- 
dominant form. 

Practically every flock of goats in the Southwest is infested and 
some years the injury is very marked. The annoyance retards the growth 
of the kids and injures the condition of flesh of the goats, but the most 
obvious loss is brought about in the reduction of the mohair clip. The 
irritation produced by the lice induces much rubbing, which of course 
pulls out and mats the mohair and there also appears to be considerable 
loss through the actual cutting of the hair by the lice themselves. Cer- 
tain large goat raisers in Texas estimate a loss of twenty per cent in the 
clip some years and often individual goats are so denuded that shearing 
is not profitable. The quality of the mohair is also said to be materially 
affected when the lice are abundant. 

The lice are present on all parts of the host, especially on the 
heavily haired portions and the whitish eggs are attached to the hairs 
next to the skin. 

The sucking louse, Linognathus stenopsis Burmeister, frequently be- 



LICE WHICH AFFECT DOMESTIC ANIMALS 347 

comes a pest of importance in goat flocks. The lice are especially in- 
jurious to the kids, and their attack together with that of the biting lice 
is thought to cause material reduction in the number of kids raised to 
maturity. On the kids the lice are present on all parts of the body but on 
the mature goats they are usually more numerous where the hair is not 
very thick. 

Control. — In proceeding against goat lice it is important to deter- 
mine whether biting or sucking lice are giving trouble. In many flocks the 
former are practically the only kind present and in such cases it is more 
economical to treat the flock with sodium fluoride in the dust form than 
to dip it. This is especially true when dipping vats are not at hand. 
We have found that a high degree of effectiveness (90 to 100 per cent 
destruction) may be obtained by applying the sodium fluoride with a 
dust gun to the flock in a pen or as the goats are driven through a 
chute. It does not seem to be necessary to drive the dust into the mohair 
especially and only a small amount — about one-third of an ounce per 
head — is necessary. 

In the experiments carried out by Mr. D. C. Parman at Uvalde, 
Texas, nicotine sulphate used at a strength of 0.07 per cent nicotine was 
found to give complete control of sucking lice but was less effective 
against the biting species. On the other hand the standard arsenical 
dip (white arsenic 8 pounds, sal soda 24 pounds, pine tar one gallon, and 
water 500 gallons) gave complete destruction of both forms of lice with 
one dipping. As the arsenical dip is probably the cheapest material ob- 
tainable it should be recommended above all others where both biting and 
sucking lice occur in a flock. Goats are usually bunched and sheared in 
the spring and fall, and following shearing is a good time to treat the 
entire flock for lice. 

LICE OF THE HORSE 

Horses are quite commonly infested with one biting and one sucking 
species, Hcematopinus asini Linnaeus and Trichodectes parumpilosus 
Piaget. It is the writer's impression that the biting louse predominates 
throughout this country, however, it is not an infrequent occurrence to 
find herds heavily infested with the sucking louse. It is probable that a 
careful study of the lice of horses will show that in certain regions one 
predominates, while in others the other form may be more abundant. 

While it is probable that both forms can breed on asses and mules it is 
certainly true that these animals are much less subject to louse attacks 
than the horse. 

Horses which are worked more or less regularly and properly groomed 
are usually troubled very little from lice, but colts and animals on the 



348 SANITARY ENTOMOLOGY 

range are frequently so heavily infested as to produce injurious effects. 
One's attention is usually attracted to the lice on account of the rubbing 
and biting of the animals which may in some cases become almost a 
mania. The hair is frequently rubbed off in spots so as to expose the 
skin in the regions where the lice are most abundant, notably around the 
base of the tail and on the neck. 

Control Measures. — On farms where comparatively few horses are 
kept the lice can most conveniently be brought under control by careful 
grooming of the animals, and an occasional light application at grooming 
time of lard with a small amount of kerosene added or raw linseed oil. 
This treatment would undoubtedly answer in the case of army horses, al- 
though it would probably be advisable in such instances as well as on 
ranges where horses are raised extensively, to install dipping vats and 
dip all animals twice at an interval of two weeks. The standard arsen- 
ical solution is the best for this purpose. This treatment is also effective 
against cattle lice. 

Where biting lice alone are concerned sodium fluoride can be applied 
very conveniently and will give complete control with one application 
at a very low cost. A powder gun may be employed and each animal 
should be generally dusted using about one ounce. This is especially 
adapted to the treatment of animals in the winter when the greasing or 
wetting of the host is undesirable. It is the winter season, too, when 
the lice are most abundant and injurious. 



IMPORTANT BIBLIOGRAPHICAL REFERENCES 

Bishopp, F. C, and Wood, H. P., 1917. — Mites and lice on poultry. 

U. S. Dept. Agr., Farmers' Bull. 801, pp. 1-26, May. 
Bishopp, F. C, and Wood, H. P., 1917. — Preliminary experiments with 

sodium fluoride and other insecticides against biting and sucking lice. 

Psyche, pp. 187-189, December. 
Hall, Maurice C, 1917. — Notes in regard to horse lice, Trichodectes 

and Haematopinus. Journ. Am. Vet. Med. Assoc, vol. 51, n. s., vol. 4, 

pp. 494-504, July. 
Herrick, G. W., 1915. — Some external parasites of poultry. Cornell 

Exp. Sta., Bulletin 359, pp. 229-268, April. 
Imes, Marion, 1918. — Cattle lice and how to destroy them. U. S. Dept. 

Agr., Farmers' Bull., pp. 1-27, February. 
Lamson, G. H., Jr., 1916. — Some lice and mites of the hen. Conn. Agr. 

Exp. Sta., Storrs, Conn., Bull. 86, pp. 171-196, March. 
Lamson, G. H., Jr., 1918. — Cattle lice and their control. Conn. Agr. 

Exp. Sta., Storrs, Conn., Bull. 97, pp. 1-17, November. 



LICE WHICH AFFECT DOMESTIC ANIMALS 349 

Osborn, Herbert, 1896. — Insects affecting domestic animals. U. S. Dept. 

Agr., Div. Ent., Bull. 5, pp. 1-302. 
Stevenson, E. C, 1905. — The external parasites of hogs. U. S. Dept. 

Agr., Bur. Anim. Ind., Bull. 69, pp. 1-44. 
Watts, H. R., 1918.— The hog louse. Tenn. Agr. Exp. Sta., Bull. 120, 

pp. 1-15, 



CHAPTER XXIV 

Diseases Carried by Fleas 1 
W. Dwight Pierce 

Fleas pass their immature stages in filth outdoors and indoors. The 
larvae breed in dirt and are usually to be found where animals are com- 
mon, but they may breed in the dirt of kennels and stables, in the open 
country, in carpets, and closets of houses and especially in cellars. They 
are always to be found where rats or mice are common. 

Because of the fact that the larva imbibes filth and the adult sucks 
blood, we should seek other possibilities of disease transmission which 
have not hitherto been investigated. Past investigations with fleas 
have dealt principally with the possibility of conveying disease by the 
bite of the adult flea. The work which has been done on flies and which 
was quoted in a preceding lecture showed that larvae could take up bac- 
teria and that these would persist into the adult stage. It is therefore 
essential in the future investigations of disease transmission by fleas that 
account be taken of the possibility of the flea larva? taking up the organ- 
ism from the filth in which they breed and retaining these organisms 
to be transmitted by the adult. That they may do this is demonstrated 
in the case of the tape worms mentioned below. 

Fleas do carry disease, that we know. But probably they can carry 
diseases which they have never been credited with. There lies our field 
of investigation. 

The arrangement of organisms transmitted by fleas follows that 
adopted for previous lectures. 



PLANT ORGANISMS TRANSMITTED BY FLEAS 

Thallophyta: Fungi: Schizomycetes: Bacteriacew 

Bacillus pestis Kitasato, the cause of BUBONIC PLAGUE of man 
and rodents, is carried by fleas. Nine species of rodents, mainly rats and 

1 This lecture was presented on October 28, 1918. It is considerably modified for 
the present edition. 

350 



DISEASES CARRIED BY FLEAS 351 

mice, are proven hosts of plague. The following fleas have been proven 
to be carriers of the organism: Xenopsylla cheopis Rothschild, Cerato- 
phyllus fasciatus (Bosc) Curtis, C. acutus Baker, C. silantiewi Wagner, 
Pulex irritans Linnaeus, Ctenocephalus cants (Curtis) Baker, Lep- 
topsylla musculi Duges and Pygiopsylla dhalae Rothschild. 

The first successful record of transmission of plague by fleas was 
made by Simond in 1898, and corroboration was first obtained by Verjbit- 
ski in 1903 and Liston in 1904. 

Many other workers have since then proven the role of the flea in 
carrying this disease. A synopsis of the evidence is presented by Herms 
in his textbook. The flea takes up the organism with the blood of the 
host. The stomach of the rat flea, Xenopsylla cheopis, is capable of 
receiving as many as 5000 germs while imbibing the blood from a plague 
rat. Both males and females may carry the infection and they may 
remain infective during an epidemic for 20 days. The Indian Plague 
Commission found the bacilli only in the stomach and rectum of the 
fleas and never in the salivary glands or body cavity and rarely in the 
esophagus. They conclude that the normal course of the bacilli is to be 
voided in the feces and to be inoculated by scratching in of the feces. 
Bacot and Martin, however, have come to the conclusion that plague can 
be transmitted during the act of biting when a temporary blocking or 
obstruction of the proventriculus takes place, causing bacillus-laden blood 
to be forced back or regurgitated into the wound, thus producing infec- 
tion. 

Bacterium tularense McCoy and Chapin, cause of a fatal RODENT 
PLAGUE which affects the California ground squirrel, Citellus beecheyi, 
may also be transmitted by fleas. McCoy and Chapin placed fleas 
(Ceratophyllus acutus Baker and C. fasciatus Bosc) with an inoculated 
guinea pig and allowed them to remain there until the animal died. They 
were then collected, and crushed and inoculated into healthy guinea pigs. 
The four animals inoculated with crushed C. fasciatus immediately after 
the fleas were removed from the dead guinea pig, died of the disease ; two 
of four inoculated after 24 hours, died; and one out of four inoculated 
after 48 hours, died. Two out of four animals inoculated with crushed 
C. acutus immediately after removal from the dead guinea pigs, died, but 
none died that were inoculated on subsequent days, although some devel- 
oped an apparently chronic form of the disease. They also succeeded in 
obtaining one actual case of transmission. About 100 fleas collected from 
an animal dead of the disease were placed in a clean cage with a healthy 
ground squirrel. It died 15 days later and presented the usual lesions 
of the plague-like disease, the bubo being in the neck. 



352 SANITARY ENTOMOLOGY 

ANIMAL ORGANISMS TRANSMITTED BY FLEAS 

Protozoa 
Mastigophora: Binucleata: Trypanosomidke 

As stated elsewhere the classification here used was recently proposed 
by Chalmers. It is especially interesting that all flea-borne diseases 
belong to the genus Trypanozoon Luhe (Lewisonella Chalmers) 2 in 
which the final stage of development in the definitive host (the insect) 
occurs in the hind gut, and infection is contaminative. 

Trypanozoon blanchardi (Brumpt), cause of a trypanosomiasis, sup- 
posedly nonpathogenic, in rodents of the genera Myoxus and Microtus 
has been found by Brumpt (1913) to develop in the flea, Ceratophyllus 
laverani Laveran and Pettit. The life cycle is identical with that of T. 
lewisi and T. nabiasi and is effected entirely in the large intestine of the 
flea. Metacyclic trypanosomes occur in the rectal ampulla and are found 
in the dejections. It is not found in the salivary glands. 

Trypanozoon duttoni (Thiroux), cause of a trypanosomiasis, sup- 
posedly nonpathogenic, in mice of the genus Mus, has been found by 
Brumpt (1913) to develop in the flea, Ceratophyllus hirundinis Curtis. 
The evolution of this species occurs in the large intestine of the flea and 
is comparable to that of T. lewisi, T. nabiasi, and T. blanchardi. It is 
not found in the salivary glands. 

Trypanozoon lewisi (Kent), cause of a trypanosomiasis, rarely patho- 
genic, in rodents of the genera Epimys, Acanthomys, Mus, Myoxus, and 
Meriones, etc., passes its cycle of sporogony in fleas (fig. 62). The life 
cycle has been investigated in Ceratophyllus fasciatus (Bosc) Curtis, 
Ctenocephalus cams (Curtis) Baker, and Ctenopsyllus niusculi (Duges) 
Wagner, and it has been shown that Pulex irritans Linnaeus, and 
Xenopsylla cheopis Rothschild may serve as true hosts. In addition 
Ceratophyllus lucifer Rothschild, C. hirundinis Curtis, Ctenophthalmus 
agyrtes (Heller) Baker, and Pulex brasiliensis Baker are recorded as 
carriers. Fantham, Stephens and Theobald summarize the life cycle 
in the flea. When infected blood is taken up by the flea, the parasites 
pass with the ingested blood direct to the mid-gut of the flea. In the 
stomach they penetrate the cells of the lining epithelium and multiply 
by division inside the epithelial cells. They first grow to a large size, then 
form large spherical bodies within which nuclear multiplication occurs. 
Any one of these large spherical bodies contains at first a number of nu- 
clei, kinetonuclei, and developing flagella, the original flagellum still re- 
maining attached for a time. The cytoplasm then divides into daughter 
2 This synonymy is according to Mesnil. Bull. Inst. Past. vol. 17, p. 190. 



DISEASES CARRIED BY FLEAS 



353 



trypanosomes which are contained within an envelope, formed by the peri- 
blast of the parent parasite. Inside the periblast envelopes are a number 
of daughter trypanosomes wriggling very actively; the envelope finally 
bursts and releases them, usually about eight, in the host cell. The 
daughter forms escaping from the host cell into the stomach of the flea 
are fully formed, long trypanosomes. They then pass into the rectum, 
where they assume a crithidial phase, and become pear-shaped. The 
kinetonucleus has traveled anteriorly past the nucleus toward the flagel- 
lum. The crithidial forms attach themselves to the wall of the rectum 
and multiply by binary fission. In this form the parasite probably 

Host I (Rodent). 5 Host II (Flea). 




SPOR0G0NY 



Host I Mice,Rats (Epimys.Acanthomys.Mus.Myoxus, Merion.es). 
Host II Fleas (Ceratophyllus.Ctenocephalus.Ctenopsylla.Pulex, 
Xenopsylla). 



LIFE CYCLE OF TRYPANOSOMA LEWISI. 

Kits. 63. (Pierce.) 

exists throughout the life of the insect. From the crithidial forms small 
infective trypanosomes develop. These are small, broad, and stumpy, 
with the kinetonucleus behind the nucleus, and the flagellum longer. 
Brumpt (1913) declares that transmission occurs exclusively by rodents 
licking up the feces of infected fleas. These feces contain little meta- 
cyclic trypanosomes which are able to traverse healthy mucous mem- 
branes. 

The life cycle as described has been figured graphically in the same 
scheme as used in previous lectures. 

Trypanozoon nabiasi (Railliet), a rabbit trypanosome, presumably 
nonpathogenic, attacks the genus Lepus and was found by Brumpt 
(1913) to be transmitted by the rabbit fleas Ctenocephalus leporis 
(Leach) Baker and Spilopsyllus leporis (Leach) Baker. The life cycle 



354 SANITARY ENTOMOLOGY 

is identical with that of T. lewisi and has metacyclical forms in the rec- 
tum. It is never found in the salivary glands. 

Trypanozoon rabinowitschi (Brumpt), a trypanosomiasis affecting 
the genus Cricetus, is carried by the fleas Ctenocephalus canis (Curtis) 
Baker, Ctenophthalmus assimilis ( Taschenburg) Baker and Ceratophyl- 
lus fasciatus (Bosc) Curtis. According to Brumpt (1913) N oiler has 
proven the development of this organism in the rectum of fleas. The 
little metacyclic trypanosomes are found in the rectal ampulla. 

Mastigophora: Binucleata: Leptomonidae 

Crithidia ctenophthalmi Patton and Strickland is parasitic in 
Ctenophthalmus agyrtes (Heller) Baker. 

Crithidia hystrichopsyllae Mackinnon is parasitic in Hystrichopsylla 
talpae (Curtis) Rothschild. 

Crithidia pulicis Porter (1911) not Wenyon (1908) is parasitic in 
Pulex irritans Linnaeus. Miss Porter described its life cycle in the 
flea. 'The preflagellate stage is probably taken up by feeding on dejecta 
of infected fleas. The preflagellates have a somewhat frail appearance. 
Division rosettes are frequent. The flagellates have relatively short free 
flagellum and a large undulating membrane. These are followed by a 
postflagellate stage in which multiplication is by longitudinal division. 
Infection is contaminative, the postflagellates in the feces being the 
source of infection. There is no evidence of hereditary transmission. 

Crithidia pulicis Wenyon is parasitic in Xenopsylla cleopatrae. 

Leishmania infantum Nicolle the cause of INFANTILE KALA 
AZAR of the Mediterranean region and Asia, is, according to experiments 
of Basile, probably naturally transmitted by the fleas Ctenocephalus 
canis and Pulex irritans. He apparently obtained the disease by taking 
fleas from bed clothes of infected people, and also from infected dogs, and 
feeding them on healthy dogs. 

Castellani and Chalmers inclined towards the Basile theory but Wen- 
yon is not convinced. Basile found Leishmania-like forms in the mid-gut 
of the flea. He also found other forms, some with flagella and some with- 
out, and concludes that there is a cycle of development with preflagel- 
late, flagellate and postflagellate forms. 

Leptomonas sp. Balfour (1906) is described from Xenopsylla cleo- 
patrae. 

Leptomonas ctenocephali (Fantham) is parasitic in the gut of the 
Ctenocephalus canis. Fantham has described preflagellate and flagellate 
forms. In experiments of Laveran and Franchini (1913) dogs, inocu- 
lated from mice infected with this organism by feeding on feces of the 
flea, died. The disease caused by this organism cannot be distinguished 



DISEASES CARRIED BY FLEAS 355 

from canine kala azar, which suggests to some writers the insect origin 
of that disease. Fantham, however, does not consider this organism 
related to Leishmania. 

Leptomonas ctenophthalmi (Mackinnon) is described as a parasite 
of C ten ophthalmitis agyrtes. 

Leptomonas ctenopsyllae (Laveran and Franchini) occurs in the gut 
of Ctenopsyllus musculi. 

Leptomonas debreuili (Brumpt) is a parasite in the squirrel flea. 

Leptomonas pattoni (Swingle) is a native to Ceratophyllus fasciatus, 
C. lucifer, and Xenopsylla cheopis. According to Fantham and Porter 
it has been found naturally in the blood of mice. Ingestion of feces of 
fleas infected with this organism has caused death or disease in white 
mice, according to Laveran and Franchini (1914). 

Mastigophora: Spirochaetacea: Spirochaetidae 

Spiroschaudinnia ctenocephali (Patton) has been described from 
Ctenocephalus canis in India. 

Telosporidia: Gregarinida: Agrippinidae 

Agrippina bona Strickland occurs in the gut of the larvae of the rat 
flea, Ceratophyllus fasciatus in England. 

Telosporidia: Haemogregarinida : Haemogregarinidae 

Haemogregarina (Hepatozoon) jaculi Balfour, the cause of 
ANAEMIA of the jerboas, Jaculus gordoni and /. orient alis, is thought 
to be carried by the flea Xenopsylla cheopis. Balfour noted large cysts 
in X. cleopatrae which Christophers thinks possibly belong to this 
species. 

Metazoa 

Platyhelmia: Cestoidea: Cyclophillidea: Taeniidae 

Dipylidium caninum (Linnaeus), the DOG TAPEWORM, has for its 
intermediate hosts the dog flea, Ctenocephalus canis (Curtis) Baker, the 
cat flea, C. canis felis (Bouche), and the human flea, Vulex irritans 
Linnaeus. It may also be carried by the dog louse Trichodectes latus 
(canis). Neumann, however, regards the fleas as most important. The 
ripe proglottids which contain the eggs of the tapeworm, by their own 
movement, pass through the host's anus and get into the fur where they 
become partly dried and disintegrated and fall to the ground. Part of 



356 



SANITARY ENTOMOLOGY 



the segments, the oncospheres, are released by the disintegration and are 
then ingested by the flea larva or the louse. Sonsino contended that the 
adult flea could not ingest the egg of this worm and Joyeux (1916) has 
demonstrated this fact. He was able to demonstrate that the larvae can 
and do ingest the egg easily. The embryos when they reach the intestine 
escape from their envelopes, the oncospheres, and penetrate into the gen- 
eral cavity. They are imbedded in the adipose tissues and are very dif- 
ficult to demonstrate. Here they remain during the metamorphosis. 
When the adult flea is formed the hexacanth immediately begins to de- 
velop, even before its host begins to feed. On the second and third days 




Development Of 
Cysticercoio 



Ripe Troglottids 
In Feces Break 
Up And Release. 
Oncospheres. >> 



Development of Tape Worm 



LIFE CYCLE OFDIPYLIDIUM CANINUM. 

The Dog Tape Worm. 
Host I. Fleas (Cte.nocephal.us canis, C.FELIS, 

PoLEX IRRITANSJ. 

Host II. Dog (Cani-s famiuaris). 
Cat ^Felis catus). 
Jackal (Cams aureus). 

Fig. 63. (Pierce.) 

it is enlarged and the primitive lacuna begins to form. From this point 
it develops into the cysticercoid. The dog or cat becomes infested by 
biting or licking up the infected fleas or lice on its body. The flea can 
spread the infection to human beings that accidentally swallow the in- 
sects. Possibly in case of children, infection takes place by kissing pets 
or by pets stealing a drink from a bowl, the contents of which are after- 
wards given to children. 



Platyhelmia: Cestoidea: CyclophUlidea: Hymenolepididae 

Hymenolepis diminuta (Rudolphi), the YELLOW-SPOTTED TAPE- 
WORM of the rat, may pass its intermediate stage in larvae of a number 
of insects of different orders. Nicoll and Minchin found the cysticercoid 



DISEASES CARRIED BY FLEAS 357 

in four per cent of rat fleas, Ceratophyllus fasciatus, and succeeded in in- 
fecting rats by feeding them on fleas. Johnston in Australia has corrobo- 
rated the fact that this flea is a host, while Joyeux has proven that in- 
fection takes place easily in the larval stage, but is impossible in the adult 
flea. Johnston has found Xenopsylla cheopis to be a host. Joyeux has 
infected larvae of Pulex irritans and Ctenocephalus cams. He found that 
the embryo develops independently of the metamorphosis of its host. 
The rodents become infected by licking up infected insects. 

Hymenolepis nana (Von Siebold), the dwarf tapeworm of rats and 
man, may possibly pass its intermediate stage in fleas. Nicoll and Min- 
chin found a cysticercoid in Ceratophyllus fasciatus resembling this 
species, and Johnston in Australia also found a similar cysticercoid in 
Xenopsylla cheopis. 

Nemathelminthes : Nematoda: Spiruridae 

Protospirura muris (Gmelin), a STOMACH PARASITE of rats and 
mice, has a larva similar to one found by Johnston encapsuled in the 
general cavity of the rat flea, Xenopsylla cheopis. 

Nemathelminthes : Nematoda: Filariidae 

Acanthocheilonema reconditum (Grassi), a cause of CANINE FIL- 
ARIASIS, possibly passes its embryonic development in fleas. Grassi and 
Calandruccio found larval nematodes in fleas, Ctenocephalus cants, C. felis, 
and Pulex irritans that they assumed belonged to the species A. recon- 
ditum. The embryos, according to Grassi, perforate the intestinal wall 
of the flea which has ingested blood containing the parasites. The latter 
make their way into the fatty tissue where they are almost always to be 
found lying singly in the fat cells. The fat cells increase in size as the 
parasites grow, the latter being curled up once or twice within the cell, 
the nucleus of which remains uninjured. The embryo undergoes four 
stages of development in the flea. There is no positive proof of the method 
of transmission. 

SUMMARY 

In summary, therefore, we may call attention especially to the fact 
that the flea carries plague, is apparently the carrier of infantile kala 
azar, and is an intermediate host of one of the human tapeworms. In 
addition it is intermediate host of various animal diseases. 

Unlike the louse-borne diseases, the life cycles of the organisms caus- 
ing flea-borne diseases are quite variable. 

The bacilli of plague and rodent plague are taken up by the bite 



358 SANITARY ENTOMOLOGY 

of the flea and are voided in its feces and obtain entrance to the host by 
the scratching in of feces of infected fleas, or by the licking up of the 
feces or the flea. 

The five trypanosomes are all taken up from the blood and pass 
through a definite life cycle in the flea, passing out of its feces, and 
obtain entrance to the host by being licked up in the feces. This may 
also happen in the case of leptomonads. 

The crithidias and leptomonads belong primarily to the fleas alone, 
and pass through their cycle of existence in the flea body and out of its 
feces and are taken up by feeding on the infected feces, probably by 
the larva. 

The tapeworms are taken up as eggs by the larvae feeding in filthy 
dirt. They develop in the flea and are taken into the vertebrate host 
when it licks up the flea from its body. 

The filaria is taken from the blood of the host as an embryo, and 
develops in the flea, but we do not know how it gets back to the 
host. 

In addition to all these diseases caused by organisms, fleas may cause 
a dermatitis. This is especially true of the chigoe, Dermatophilus pene- 
trans, which becomes fixed to its host and sometimes even causes AIN- 
HUM, or the loss of a member, such as a toe. It will be discussed in the 
next lecture on fleas. 

REFERENCES 

Bacot, A. W., and Martin, C. J., 1914. — Journ. of Hygiene, Plague Sup- 
plement III, Jan. 14, 1914, pp. 423-439. 
Brumpt, E., 1913.— Bull. Soc. Path. Exot., vol. 6, pp. 169-170. 
Fantham, H. B., Stephens, J. W. W., and Theobald, F. V., 1916.— The 

Animal Parasites of Man. 
Herms, W. B., 1915. — Medical and Veterinary Entomologjr. Macmillan 

Co., 393 pp. 
Johnston, J. H., 1913. — Proc. Roy. Soc. Queensland, vol. 24, pp. 63- 

91. 
Joyeux, Charles, 1916.— Bull. Soc. Path. Exot., vol. 9,, No. 8, pp. 578- 

579. 
Laveran, A., and Franchini, G., 1913. — C. R. Acad. Sci., Paris, vol. 47, 

No. 18, pp. 744-747. 
Laveran, A., and Franchini, G., 1914. — Bull. Soc. Path. Exot., vol. 7, 

pp. 605-612. 
Liston, W. G., 1905. — Journ. Bombay Nat. Hist. Soc, vol. 16, pp. 

253-273. 
McCoy, G. W., and Chapin, C. W., 1912. — Journ. Infect. Diseases, vol. 

10, No. 1, pp. 61-72. 



DISEASES CARRIED BY FLEAS 359 

Porter, Annie, 1914. — Parasitology, vol. 4, No. 3, pp. 237-254. 
Seurat, L. G., 1916. — Bull. Scient. France et Belgique, ser. 7, vol. 49, 

fasc. 4. 
Simond, P. L. S., 1898.— Ann. de l'Inst. Pasteur, vol. 12, p. 625. 
Ver jbitski, D. T. 5 1908.— Journ. of Hygiene, vol. 8, p. 162. 



CHAPTER XXV 

The Life History and Control of Fleas 1 
F. C. Bishopp 

The importance of flea control probably needs no further emphasis 
than that already apparent after reading the lecture on the relation 
of fleas to disease. It should be borne in mind that the plague has been 
one of the most terrible scourges in the history of the world and that its 
reduction to an inconspicuous place in Europe and the western hemisphere 
has been the result of the knowledge of the relationship between rats and 
fleas and Bacillus pestis, the causative organism of the disease. Aside 
from the part which fleas play in the transmission of this dreaded malady 
and certain other human ailments, they are often of decided importance 
on account of the annoyance to man produced by their crawling about 
over the body and biting. The susceptibility to attack of individuals 
seems to vary greatly. In many cases a few fleas produce but little 
annoyance and the bites leave no after effect. In other instances the 
crawling of the fleas produces much annoyance and the bites have been 
known to form lesions of more or less serious character and often slow 
to heal. 

To proceed intelligently with flea control it is important to have a 
good general knowledge of their habits and distribution. Eleven species 
of fleas have been shown capable of carrying plague. Eight of these 
have been found to occur on one or more species of rat (Epimys spp.) 
and two on ground squirrels. Of these, the Indian rat flea undoubtedly 
plays the principal role in the transmission of bubonic plague. The 
following list includes most of the forms which may be considered 
important to man either as vectors of disease organisms or as annoyers: 
Pulex irritans, Ctenocephalws canis, Ct. felis, Ceratophyllus fasciatus, C. 
anisus, C. acutus, Xenopsylla cheopis, X. scopvlifer, Ctenophthalmus 
agyrtes, Dermatophilus penetrans, Echidnophaga gallinaceus, Hoplopsyl- 
lus anomalus. 

The host relations of fleas are very important, as has been seen by 
considering the relationship of the insect to disease transmission. Unfor- 
tunately most of the fleas are not very closely restricted to certain hosts, 
especially when forced by hunger to seek blood. It might be stated at 

1 This lecture was read November 4, 1918. 

360 



THE LIFE HISTORY AND CONTROL OF FLEAS 361 

the outset that all fleas are dependent upon blood for their existence. 
There is considerable variation in the degree to which certain species are 
restricted as regards their host, and we should not go too far in drawing 
conclusions as to whether certain species will not feed on certain hosts 
as our judgment is based usually on a comparatively small number of 
experiments under more or less artificial conditions, or upon examinations 
of a small number of host species, often in restricted districts. 

Fleas pass through four distinct stages — egg, larva, pupa (in a 
cocoon), and adult. The eggs are readily seen with the naked eye, espe- 
cially when on a dark background. Most of them are deposited by the 
females while the latter are on the host. They fall off the host, mostly 
dropping in the bedding material where they hatch in from two to twelve 
days. This is responsible for a concentration of the adults about the 
sleeping places of the hosts, and favors them by being within easy reach 
of the hosts, both old and young, and also in supplying the larvae with 
the partially digested blood excreted by the adult fleas, for food. The 
number of eggs laid varies greatly according to species, availability of. 




Fig. 64. — Larva of the European rat flea, Ceratophyllus fasciatus. Greatly enlarged. 
(Bishopp.) From U. S. Dept. Agr., Bull. 248, fig. 3. 

food for adults, etc. Bacot, of the Lister Institute, has counted as 
many as 448 eggs deposited by a female human flea. Comparatively 
few are deposited each day but the egg laying may be extended over many 
weeks. 

The Larvae. — The larvae are whitish, legless, and eyeless maggots, dis- 
tinctly segmented and provided with numerous hairs (fig. 64). They 
are usually less than one-fourth of an inch in length when grown, and quite 
active, disappearing quickly in breeding material. Larvae of some of 
the larger species may considerably exceed this length. They are to be 
found in the dust in which vegetable and animal particles are mixed. 
The larval stage is extremely variable, mostly depending on temperature, 
abundance of food, and degree of moisture and humidity. The length of 
this stage has been found to range from one to twenty weeks. Under 
favorable conditions from one to three weeks may be taken as the usual 
length of the period. 

The Pupa. — All flea larvae spin cocoons in which the pupa is 
formed. These are oval and not easily seen on account of the numerous 
particles of dust, sand, etc., which is woven in or stuck to the silken 
cocoon. This stage ranges from a week to nearly a year. The extreme 
long periods were observed by Bacot to take place only in cool weather. 



362 



SANITARY ENTOMOLOGY 



With the Indian rat flea the period was greatly lengthened when the 
mean temperature fell below 65° F., human flea below 50° F., and the 
European rat flea below 40° F. In cooler climates the winter is probably 
passed in this stage but in warmer countries adult activities never cease. 




Fig. 65. — The dog flea (Ctenocephalus cants)-, a, Egg; b, larva in cocoon; c, pupa; d, 
adult; e, mouth parts of same from side; f, antenna; g, labium from below; b, c, d, 
much enlarged; a, e, f, g, more enlarged. (From Howard.) From U. S. Dept. 
Agr., Bull. 248, fig. 3. 

The adult fleas often remain in the cocoons for weeks and emerge when 
disturbed. 

Life Cycle. — The cycle is completed under favorable conditions in 




Fig. 66. — The human flea, Pulex irritans: Adult female. Greatly enlarged. (Bishopp.) 



one to four weeks, but it may extend to one and one-third years in 
extreme cases. 

Length of Life of Adult Fleas. — A knowledge of the length of life of 
the adults is of much importance in relation to control measures and 
disease dissemination. Under cool, moist conditions Bacot found the 
human flea to live 125 days, the European rat flea 95 days, the dog flea 



THE LIFE HISTORY AND CONTROL OF FLEAS 363 

58 days, the Indian rat flea 38 days, and the bird or chicken flea (Cera- 
tophillus gallinae) 127 days. When fed daily this longevity was greatly 
increased; human flea 513 days, European rat flea 106 days, dog flea 
234 days, Indian rat flea 100 days, and the bird flea 345 days. Mitzmain 
found the European rat flea to live 160 days in California and the ground 
squirrel flea (Ceratophyllus acutus) 64 days. In warm weather the 
longevity without food is but a few days. 

The human flea (Pulex irritans) (figs. 66, 67) was formerly thought 
to restrict its attention largely to man. Investigators have found, how- 
ever, that it probably develops normally on the hedgehog and others 
state that it is occasionally found on dogs and cats, especially during the 
winter. Our own observations indicate that it is a very common parasite 
of hogs ; so much so in fact that it might be called the hog flea instead 




Fig. 67. — The human flea, Pulex irritans: Adult male. Greatly enlarged. (Bishopp.) 
From U. S. D. A. Bull. 248, figs. 5, 6. 

of the human flea. Also that it may be found in considerable numbers 
on dogs at all times of the year even in regions where it is not a pest 
of importance to man. It has been taken on several species of rats, but 
in limited numbers. This form appears to be well adapted to a free 
existence, usually leaving the host after partaking of a blood meal and 
this habit may tend to make it of greater importance as a disseminator 
of disease. It has almost world-wide distribution but its abundance in 
different regions varies greatly. In the United States it is very prev- 
alent in California and the Southwestern States where it is the principal 
cause of flea annoyance to man. 

The dog and cat fleas (Ctenocephalus cants Curtis and Ct. felis 
Bouche (fig. 65) ma}^ be discussed together as their habits appear to be 
very similar and as some authors still believe they are not distinct species 
but only varieties. They have a rather wide range of hosts, including the 
dog, cat, man, and a number of wild animals, especially of the dog and 



364 SANITARY ENTOMOLOGY 

cat family. They are occasionally found on rats. They are quite widely 
distributed throughout the temperate and tropical parts of the world. 
In the United States they often occur as household pests, and in the 
Central and Eastern States they usually take the place of the human flea 
as parasites of man, most of the outbreaks in these regions being from 
either one or the other of these species. 

The European rat flea Ceratophyllus fasciatus Bosc is rather 
closely restricted to the several species of rats and mice but it has been 
found to bite man in the absence of its preferred hosts and probably 
also will feed on other animals. It is the predominant rat flea in th<* 
United States and over the greater part of Europe, and in this region 
must be considered one of the principal vectors of plague. In the tropics 
it is much less abundant, occurring only in the cool season. 




Fig. 68. — The European rat flea, Ceratophyllus fasciatus: Adult female. Greatly 

enlarged. (Bishopp.) 

The Tropical or Indian rat flea (Xenopsylla cheopis Roth.) is 
undoubtedly the principal disseminator of bubonic plague in India and 
other parts of Asia. It is also now to be found in practically all the 
other tropical and subtropical countries of the world, but it is often 
restricted to the seaport towns, as in the case of the United States, where 
it appears not to have penetrated far inland. This species is primarily a 
rat flea, being taken on all species of rats and mice, but it feeds readily 
upon man and also will attack small domestic animals and some wild ones. 

The mouse flea (Ctenopsylla musculi Duges) is to be found in many 
parts of the world but is especially abundant in Mediterranean Europe, 
Australia, and the southern part of the United States. It is often found 
in numbers on rats as well as mice, but rarely bites man even in the 
absence of its preferred hosts. 

The Asiatic rate flea {Ceratophyllus anisus Roth.) appears to take 
the place to a large extent of the European rat flea, in Japan and portions 
of northeastern China. A species of groundhog flea (Ceratophyllus 



THE LIFE HISTORY AND CONTROL OF FLEAS 365 

silantiewi Wagner) occurs in numbers on the "tarbagan" or groundhog 
in Manchuria and was thought to be concerned in the transmission of 
plague from that host to man in the recent Manchurian outbreak. How- 
ever, subsquent investigations apparently failed to substantiate this 
theory. 

The field mouse flea (Ctenophthalmus agyrtes Heller) occurs in Eng- 
land and other parts of Europe. It is common on voles and field mice 
and also on rats living in the open. It has no inclination to bite man. 
This species probably plays little part in the dissemination of plague, 
but when the disease gets among wild rodents it no doubt would aid 
in spreading it from animal to animal. 

Pygiopsylla ahalae Rothschild has been shown capable of carrying 
plague. It is an East Indian Island species and according to De Raadt 




Fig. 69. — The sticktight flea, Echidnophaga gallinacea: Adult female. Greatly en- 
larged. (Bishopp.) From U. S. Dept. Agr. Bull. 248, figs. 2, 8. 

it is abundant on rats in coffee plantations in Java, but rare on rodents 
in buildings. He avers that the species of fleas found on rats may be 
used as an index to the source of the rat population of a given place. 

The squirrel fleas (Ceratophyllus acutus Baker and Hoplopsyllus 
anomalus Baker) are abundant in the western United States on ground 
squirrels. They have been shown capable of transmitting plague, and 
both feed readily on man and will feed on rats. 

The sticktight flea {Echidnophaga gallinaceus Westwood) (figs. 69, 
70) is an important pest of poultry in the southern United States. This 
species is widely distributed in the subtropical and tropical parts of the 
world. It atttacks several wild birds in addition to domestic species and 
has been taken on rats in numbers. It bites man with avidity. 

The chigoe or penetrating flea (Dermatophilus penetrans Linnaeus) 
is troublesome in the West Indies, Mexico, and northern South America, 
and has been introduced into West' Africa and from there to India. 
It burrows into the skin of the feet, especially around the toenails. Many 



SANITARY ENTOMOLOGY 

animals, including man, hogs, dogs, cats and the larger domestic animals, 
are attacked. 

The flea (Xenopsylla scopulifer Rothschild) occurs on rats in Ger- 
man East Africa. It is closely allied to X. cheopis and partially replaces 
that species in the region mentioned. Its possible relations with plague 
transmission have not been determined. 



FACTORS INFLUENCING ABUNDANCE OF FLEAS 

There is a very close correlation between various climatic factors and 
flea abundance. This applies to practically all species in greater or 
less degree. In the United States it may be said that in general fleas 




Fig. 70. — Head of rooster infested with the sticktight flea (Echidnophaga gallinacea). 
Somewhat reduced. (Bishopp.) From U. S. Dept. Agr., Bull. 248, fig. 7. 



are more abundant during moderately warm weather when there are 
frequent rains or high humidity. The effect of seasonal and climatic 
conditions on fleas has a very important bearing on the plague. This 
has been well shown by the Indian Plague Commission which found that 
there is a rather close correlation between the abundance of fleas and the 
prevalence of the disease, and that flea abundance in turn depended upon 
climatic conditions. They showed that in the case of the European rat 
flea there is a marked decrease in numbers with the oncoming of the hot, 
dry season. These fleas begin to disappear in early April and from May 
15 to November not a single specimen is seen. The Indian rat flea, 
which is the principal plague conveyer in that region, was found to be 
above the mean average in number during the period from November to 
May, with the maximum about April. During the rest of the year — June 
to September — the flea prevalence is below the mean, the absolute minimum 



THE LIFE HISTORY AND CONTROL OF FLEAS 367 

being reached in August to September, the maximum being six times less 
than in April. The plague season in the districts where these observa- 
tions were made is from February to May, inclusive. The maximum is 
usually reached early in May, sudden decline being experienced with 
the dropping off in numbers of the fleas early in June. 

The degree of annoyance to man from fleas depends to a large extent 
upon the relative abundance. Thus in the southern part of the United 
States, while fleas are active throughout the year, they are reduced so 
low during the winter months that they confine their attacks largely to 
smaller animals. During the spring the breeding increases rapidly and 
often severe outbreaks are experienced. In the Northeastern States these 
outbreaks are more frequent during the latter part of summer and early 
fall. 

There is also marked correlation between the character of soil and 
flea abundance. Sandy land is uniformly more conducive to flea develop- 
ment than the heavy soils. However, soils with a large amount of humus 
seem also to favor flea breeding. We do not expect to encounter wide- 
spread flea abundance in black land regions, but this does not interfere 
with severe local outbreaks. 



CONTROL OF FLEAS 

The general consideration of flea control must be governed by the 
conditions under which one is working. When we consider regions where 
plague is known certainly not to exist, little concern need be felt over 
the presence of an occasional flea, and all that is necessary is to take 
precautions that they do not become annoyingly abundant. Occasionally 
premises already infested ma} T be encountered and in such cases it is neces- 
sary to know what steps to take to reduce the numbers immediately. On 
the other hand, in regions where the presence of plague may be suspected, 
the elimination of all fleas is desirable, and one must give attention to 
the scattered fleas as well as the heavy infestations. Of course in such 
situations the prime move should be against the rats which act as hosts 
for both the plague bacillus and the fleas which carry it. In cases where 
the plague has become established in rural districts among ground 
squirrels or other native rodents, their destruction also requires attention. 
The procedure in such cases must necessarily be governed by the dura- 
tion of occupancy of a given place. For permanent elimination rat- 
proofing is essential. This consists in the elimination of all loosely con- 
structed buildings and the concreting of floors, basements and wharves. 
While the rat-proofing is going on war should be waged against the 
rats by poisoning, shooting, and trapping. Where plague is known to* 
exist in a city or village being cleared of rats 3 every precaution should 



368 SANITARY ENTOMOLOGY 

be taken against flea bites. Workers should be provided with closely- 
fitting clothes and leggings and certain other methods of body isolation 
as discussed in a subsequent paragraph. 

When operating in regions where plague is suspected, it is also im- 
portant to choose locations for troops which are apt to be free from 
rats. The billeting of men in old buildings, warehouses, barns, etc., should 
under such conditions be entirely avoided. 

Control of Hosts. — To k^ep down heavy infestations of those species 
of fleas which are annoying to men and animals, one of the essential steps 
is to exercise control over the hosts. Of course, this principle is involved 
in the elimination of rats and squirrels in plague areas. W T hen an infes- 
tation is encountered, the first thing that should be inquired into is the 
possible hosts and their haunts. Usually the main trouble can be traced 
to the sleeping places of dogs, cats, hogs, or to hen houses, or spaces 
beneath houses and barns frequented by poultry. In the case of the 
human flea the infestation may be more or less general over the premises, 
but there are nearly always centers where they are concentrated and 
often these are associated with pet animals. When the principal breeding 
places have been located the hosts should be destroyed if possible, or 
freed from adult fleas, and kept under control. A definite sleeping 
place should always be provided for dogs and cats, and these may be 
kept free from fleas, after treatment, by cleaning out the beds regularly 
and spraying with coal tar disinfectant. The host animals may be freed 
of fleas by washing them thoroughly in a 3 per cent solution of creolin 
and water, or by using any other standard saponified creosote compound. 
Kerosene emulsion made according to the formula : One pound soap, two 
gallons kerosene, one gallon water, reduced one to nine, is also very effec- 
tive. In the case of cats these substances must be washed out of the fur 
with warm water and soap shortly after treatment to avoid burning of 
the skin. 2 

Where premises are heavily infested with adults it is first necessary to 
destroy this stage and this may be accomplished by fumigation, if the 
building is fairly tight, either with hydrocyanic gas, five ounces cyanide 
per thousand cubic feet ; or by burning sulphur at the rate of four pounds 
per thousand cubic feet. As has been pointed out, many adults remain 
quiet in pupa cases or may be buried in sand or cracks where they are 
somewhat protected from the effects of the gas. In destroying the imma- 
ture stages we can take advantage of the destructive effect of extremes in 
moisture or dryness. Where complete flooding of infested areas is feasible, 
this has been known to accomplish the destruction of all stages. In other 
cases, loose boards and trash should be removed and burned and the 

2 Powdered derris has been found very efficacious in destroying fleas on animals. 
One grain scattered in the hair of a dog will kill all fleas present. 



THE LIFE HISTORY AND CONTROL OF FLEAS 369 

infested areas sprinkled heavily with salt and wet down by sprinkling. 
Repeat the wetting operation at intervals of five to ten days, according 
to the condition of the soil. Usually two or three treatments are 
sufficient. 

Where fumigation can not be practiced and it is desirable to get rid 
of the adults at once without waiting for them to starve, a number of 
procedures may be followed. If in habitations, sprinkling flaked naphtha- 
lene over the floor at the rate of four or five pounds to each two or three 
hundred feet, closing the rooms up for a few hours, and then sweeping 
the material to the next room together with the stunned fleas is very 
effective. Pyrethrum may be used in a similar way. In barns and base- 
ments spraying with kerosene emulsion will accomplish the destruction 
of most of the active adults. 

Where adults are abundant in sheds, barns, and hog yards, we have 
found that the light but general spraying of the infested areas with 
creosote oil (at least 10 per cent tar acids) will accomplish striking 
results. 

In buildings where fleas are breeding in the cracks of the floors or 
under rugs and carpets, these should be removed, the house thoroughly 
swept and the floors washed with strong soap or lye water, or if feasible, 
they may be sprayed with gasoline or kerosene emulsion. The free use 
of sweeping compounds and floor oils will largely eliminate subsequent 
trouble. 

In treating premises infested with sticktight fleas it is important that 
all fowls be excluded from beneath houses and barns. These conditions 
prevail largely in the South where this pest becomes annoying. If this 
precaution is taken and the fowls are kept in sheds which admit plenty of 
sunshine and air, and the infested places be treated with salt and water 
no attention need be given to the fleas upon the host. 

Repellents, Isolation and Trapping. — The wearing of shoes and leg- 
gings will largely exclude the chigoe flea. While cleaning up infested 
premises it has been found that the laborers can exclude the fleas and at 
the same time catch large numbers of them by wrapping the legs with 
paper covered with tanglefoot. To prevent fleas attacking one at night 
the use of flaked naphthalene or pyrethrum dusted in the bed clothing will 
give a degree of immunity. 

Since fleas are comparatively limited in their ability to jump (greatest 
height of any species about eight inches, greatest horizontal distance 
about thirteen inches) cots and beds may be protected by isolating their 
legs in pans of water or by wrapping them with paper or cloth treated 
with tanglefoot. The bed clothing should, of course, be kept tucked up 
so as not to reach near the floor and individuals should remove all clothing 
and be free from fleas when entering the bed. 



370 SANITARY ENTOMOLOGY 

To prevent spread of fleas from regions where plague is present, care 
should be taken not to allow rats and mice to gain access to packed 
materials, and fumigation of clothing and other articles should be prac- 
ticed en route or at destination. Precautions against the transference of 
rats from ships to land or from the docks to ships when in port are 
very essential. All boats should be kept at least four feet away from 
the docks and all hawsers should be provided with rat guards. These 
are metal discs at least two feet in diameter fastened to the rope between 
the ship and dock. Gangplanks should never be left down day or night, 
except when actually in use and care should be taken not to transfer 
rats with cargo. This is often very difficult, if not impossible. 

Fumigation of ships when entering port is, of course, the safest plan 
to follow, especially if they have touched ports where plague may be 
present. At the present time this is practiced in nearly all the important 
ports of the world. Sulphur dioxide applied under pressure by the so- 
called Clayton method, and hydrocyanic acid gas are employed. This 
fumigation, if properly done, accomplishes the destruction of the rats, 
fleas and other life aboard. The hydrocyanic acid gas appears to be 
giving best results and danger of damaging cargoes is lessened. 

Since fleas are largely attracted to moving objects it is possible to 
collect great numbers of them by allowing men with their legs wrapped in 
paper treated with tanglefoot to walk about over the infested area. Where 
fleas are less abundant, and especially in places where plague is suspected, 
the use of animal hosts to collect the fleas may be employed. Guinea 
pigs, white rats, or rabbits may be used for this purpose. After being 
in the infested premises for some time, the fleas may be killed by placing 
the trap animal in a jar and applying chloroform and when the 
anesthesia is complete, the fleas will either drop off or remain on the 
surface of the hair where they can readily be picked off and placed in 
containers before reviving. Of course the animal may be treated with 
kerosene emulsion or other insecticides. The effectiveness of animals as 
traps varies with the species of fleas concerned. The Indian rat fleas and 
European rat fleas do not go freely to guinea pigs but are caught in 
great numbers on tanglefoot on man. The squirrel flea will go to guinea 
pigs very readily. 

Dr. Hindle has described a flea trap used in China. It consists essen- 
tially of a cylinder covered with tanglefoot, and protected against stick- 
ing to objects by an outside cylinder with openings to allow the fleas to 
strike the sticky surface. This can be rolled about on the floor of the 
infested rooms. 

Medical Treatments for Flea Attach. — Flea bites seldom need medical 
treatment. However, some people are so susceptible that irritation and 
itching follow the bites, and some develop ulcers. The use of disinfectant 



THE LIFE HISTORY AND CONTROL OF FLEAS 371 

solutions are advised for the latter, and cooling applications, such as 
mentholized or camphorated ointments for the itching. In the case of 
infestations of the chigoe the insect should be promptly removed by 
excision and the part kept as free from infection as possible. 

LIST OF REFERENCES 

Bacot, A. W., 1914. — A study of the bionomics of the common rat fleas 
and other species associated with human habitations. With special 
reference to the influence of temperature and humidity at various 
periods of the life history of the insect. Journ. Hyg., Plague Supple- 
ment III, Jan. 14, pp. 447-654. 

Bacot, A. W., 1914. — The effect of the vapors of various insecticides 
upon fleas at each stage in their life history and upon the bedbug in 
its larval stage. Journ. Hyg., Plague Supplement III, Jan. 14, pp. 
665-681. 

Bacot, A. W., and Ridewood, W. G., 1914. — Observations on the larvae of 
fleas. Parasitology, vol. 7, No. 2, June 19, pp. 157-175. 

Bacot, A. W., and Petrie, G. F., 1914. — The fleas found on rats and other 
rodents living in association with man and trapped in the towns, 
villages and Nile boats of Upper Egypt. Journ. Hyg., vol. 14, No. 4, 
pp. 498-508, Dec. 23. 

Bishopp, F. C, 1915.— Fleas. U. S. Dept. Agr., Bull. No. 248, Aug. 14, 
31 pp. 

Bishopp, F. C, 1915. — Fleas as pests to man and animals, with sugges- 
tions for their control. U. S. Dept. Agr., Farmers' Bull. 683, Nov. 
8, 15 pp. 

Canalis, P., 1916. — Some experiments on the insecticidal action of Clay- 
ton Gas. Bull. Mens. Office Internal;. d'Hyg. Publique, vol. 7, No. 3, 
March, pp. 457-463. 

Chick, Harriette, and Martin, C. J., 1911. — The fleas common on rats in 
different parts of the world and the readiness with which they bite 
man. Journ. Hyg., vol. 11, No. 1, April 8, pp. 122-136. 

Conradi, A. F., 1902. — Remedies for fleas. N. H. Agric. Exp. Station, 
Bull. No. 94, October, pp. 89-92. 

Creel, R. H., 1915. — Hydrocyanic acid gas; its practical use as a routine 
fumigant. U. S. Pub. Health Rpts., vol. 30, No. 49, Dec. 3, pp. 3537- 
3550. 

Creel, R. H., and Faget, F. M., 1916. — Cyanide gas for the destruction 
of insects. U. S. Pub. Health Rpts., vol. 31, No. 23, June 9, pp. 
1464-1475. 

De Raadt, O. L., 1915. — Contribution to the knowledge of the epidemi- 



372 SANITARY ENTOMOLOGY 

ology of plague in Java. Meded. Burgerlijk. Geneesk. Dienst Ned.- 

Ind., pt. 4, pp. 20-38. 
Howard, L. O., 1909.— House Fleas. U. S. Dept. Agr., Cir. No. 108, 4 pp. 
Illingsworth, J. F., 1915. — Hen Fleas. The Hawaiian Forester and Agri- 
culturist, vol. 12, No. 5, May, pp. 130-132. 
Jennings, A. H., 1910. — Rats and Fleas in relation to bubonic plague, 

with special reference to Panama and the Canal Zone. Sept. 14, 

12 pp. 
Kitasato, 1909. — Rat fleas, with their special reference to the transmis- 
sion of plague in Japan. Trans. Bombay Med. Congr., p. 93. 
Liston, W. G., 1904. — Plague, rats and fleas. Journ. Bombay Nat. Hist. 

Soc, vol. 16, p. 253. 
Liston, W. G., 1914. — Report of the Bombay Bacteriological Laboratory 

for the year 1913. Bombay, Govt. Central Press, 24 pp. 
McCoy, G. W., and Mitzmain, M. B., 1909. — Experimental investigation 

of biting of man by fleas from rats and squirrels. U. S. Pub. Health 

Repts., vol. 24, No. 8, Feb. 19, 7 pp. 
Martin and Rowland. — Observations on rat-plague in East Suffolk. Ap- 
pendix to the report of the medical officer to the Local Govt. Board. 
Mitzmain, M. B., 1910. — General observations on the bionomics of the 

rodent and human fleas. U. S. Pub. Health Bull. No. 38, 34 pp. 
Neumann, L. G., 1914. — Parasites and parasitic diseases of the dog and 

cat. Paris : Asselin et Houzeau, 348 pp. 
Nuttall, G. H. F., Strickland, C, and Merriman, G., 1913. — Observations 

on British rat fleas. Parasitology, vol. 6, No. 1, April 17, 19 pp. 
Raynaud, L., 1909. — Prophylaxis de la peste en Algerie. Revue D'Hig. 

et de Police Sanit., vol. 31, p. 101. 
Reports on Plague Investigations in India, Journ. Hyg. (1906), vol. 6, 

No. 4; (1907), vol. 7, No. 3, pp. 323-476; vol. 7, No. 6, p. 693; 

(1908), vol. 8, No. 2, pp. 162-308; (1910), vol. 10, No. 3, pp. 315- 

568; (1912), vol. 12, Plague Supplement II, pp. 300-325. 
Rothschild, N. C, 1906. — Note on the species of fleas found upon rats in 

different parts of the world. Journ. Hyg., vol. 6, p. 483. 
Shipley, A., 1908. — Rats and their animal parasites. Journ. Econ. Biol., 

vol. 3, No. 3, p. 61. 
Swellengrebel, N. H., 1913. — Record of observations on the bionomics of 

fleas and rats and other subjects, bearing on the epidemiology of 

plague in Eastern Java. Meded. Burgerlijk. Geneesk. Dienst Ned.- 

Ind., vol. 2, pt. 1, 90 pp. 
Tiraboschi, C, 1904. — Les rats, les souris et leurs parasites cutanes. 

Archiv. Parasit., vol. 8, p. 161. 
Van Dine, D. L., 1908. — Report of the Entomologist. Ann. Rept. Hawaii 

Agr. Exp. Sta. for 1907, May 26, pp. 35-37. 



THE LIFE HISTORY AND CONTROL OF FLEAS 373 

Verjbitski, D. T., 1908. — The part played by insects in the epidemiology 

of plague. Journ. Hyg., vol. 8, p. 162. 
Waterston, J., 1916. — Fleas as a menace to man and domestic animals, 

their life history, habits, and control. British Museum (Natural 

History) Economic Series No. 3, 20 pp. 



NOTES ON THE CHIGOE, DERMATOPHILUS PENETRANS 

W. Dzciglit Pierce 

Mr. Bishopp has mentioned the chigoe in his lecture, but I believe 
this exceedingly interesting flea is deserving of a more extended state- 
ment. In South and Central America it is also known as La Nigua. 
It breeds in the flesh of man and animals, attacking the pig, cow, goat, 
sheep, horse, dog, cat, lion, and gorilla and probably other vertebrates. 

When the female is impregnated she attaches herself to the skin, bores 
in and remains stationary. When the eggs are mature they are either 
passed out while the female is fixed to the skin, or the flea ma} 7 become 
detached. The female while attached swells to a great size. The larvae 
breed in dirt and pupate in a cocoon. The favorite points of attack are 
on the heels, balls of foot, palm of hand, and between the fingers, although 
they attack other parts of the body. 

The attack is very painful, and in severe cases may result in ainhum, 
the loss of a member, especially a toe. Brumpt says this flea frequently 
inoculates the germs of tetanus, Bacillus tetani. This belief is also held 
by Quiros, who notes the large number of cases of tetanus following nigua 
attack. 

In cases of heavy infestations Quiros uses a pomade composed as 
follows : 

Salicylic acid 2.5 grams. 

Ictiol (ichthyol) 10.0 " 

Yellow vaseline 10.0 " 

In a few days the infested area encrusts and falls off, leaving the skin 
free from parasites. 

In cases which might lead to amputation Quiros bathes in petroleum. 
He advises against the use of iodine, which is dangerous in these cases. 

Prevention of breeding, restriction of hogs from wandering around 
habitations, wearing of shoes, and cleanliness are prophylatic measures. 



CHAPTER XXVI 

Cockroaches 
A. N. Caudell 

Contending with bedbugs for general unpopularity come cockroaches, 
noisome creatures scarcely less widely known, or less thoroughly disliked, 
than those smaller odorous and odious pests. The importance of roaches 
in houses and camps is considerable, not only as unsanitary and disgust- 
ing vermin, but as mechanical carriers of disease, and also very likely 
as intermediary hosts to certain disease-causing organisms. Experiments 
have shown these insects eminently fitted for both roles, and their impor- 
tance warrants attention by housekeeper and sanitarian. 

No more offensive insect frequents the habitation of man than the 
cockroach. These insects have long been known as pests of the house- 
hold and are found throughout most of the civilized world, especially in. 
temperate and tropical regions. The ancients are said to have called them 
lucifuga, by reason of their nocturnal habits, but the more modern name 
cockroach, or the briefer designation roach, is the one by which they 
are now universally known. Certain species are, however, given special 
common names, which may vary in different regions, as water bug, Croton 
bug, German roach, etc., which are names by which the little, brown, 
house roach is known in various places. 

Not all cockroaches are loathsome creatures of disgust, in fact there 
are very few of the many hundreds of described forms that are of any 
material economic importance. Some species of roaches are handsome in 
form and color, in some cases resembling certain beautifully colored 
beetles, a decided contrast to the flat noisome creatures of the kitchen. 

Economically, roaches are of importance only as household pests 
and disease disseminators, there being but comparatively few instances 
of their injuring living plants or doing other damage to things out of 
doors. But in houses and camps they injure many things, defile food in 
pantries, eat paint from pictures, covers from books, glue from stamps, 
and gnaw holes in clothing. The}' will devour almost anything, and have 
been recorded as biting off eyelashes, gnawing toenails, and biting the 
greasy fingers of sleeping children. 

As a rule but one species of roach occurs at one place in injurious 
abundance, two or more forms rarely occurring together in any number. 

374 



COCKROACHES 375 

When numerous they congregate, especially in kitchens where it is warm, 
damp, and not overly clean. On shipboard they often abound to such an 
extent as to cause much damage, in some cases entire supplies of certain 
foods being spoiled by eating, or rendered nauseous by their contact, a 
disagreeable odor being imparted by secretions from certain scent-glands 
situated in the bodies of the insects. The readiness with which they are 
transported with food supplies make their introduction into military 
and other camps a matter of great probability, and when once infested, 
such places are soon thoroughly stocked with these skulking creatures. 

BIOLOGY 

The life histories of our household roaches are very similar. The eggs 
are deposited incased in an oblong, leathery pod, called an ootheca, and 
containing several eggs each, arranged in two longitudinal rows. In some 
cases this ootheca is carried around for some time by the mother roach, 
partially protruding from the tip of the abdomen. But generally they are 
deposited in some cranny and sometimes the ootheca of Peri planet a is 
glued in folds of clothing, or in a leaf if of outdoor occurrence, and 
covered over with bits of material chewed off by the insect. I have myself 
seen instances of this, once on a garment and twice on leaves, and the 
recognition of the ootheca in such cases is not at all clear until it is 
uncovered. 

When first hatched from the egg the young roach resembles the adult 
in general form, but is apterous and the body is soft and whitish in color. 
Soon, however, the chitin becomes oxidized and the normal color appears. 
A number of molts occur during growth, the old skin splitting along the 
dorsal line of the thorax, and through this slit the insect emerges, the 
process being one requiring some considerable exertion ; every part of 
the body sheds its old covering, antennae, feet and all. The freshly molted 
roach, like one newly hatched, is whitish in color, but a few hours serve 
to restore the natural colors. In the last two instars the wings appear in 
a rudimentary condition, at the last molt appearing fully developed. 
This appearance of rudimentary wings is the only character separating 
the stages of the roach which correspond to larva and pupa of insects 
with complete metamorphoses. The terms larva and pupa are not gen- 
erally applied to insects with incomplete metamorphoses, the term nymph 
being there used, the degree of development being indicated by the number 
of the instar, or period between two molts. A single roach may produce 
several egg-masses in a season, and in the common house species the period 
of development from egg to adult varies with the food supply, climatic 
conditions, etc. 

While in some tropical and subtropical regions certain species of 



376 SANITARY ENTOMOLOGY 

Blaberus, Leucophaea, etc., occur in houses, the main forms with which 
the sanitarian has to deal comprise but four species, Blatta orientalis, 
Blattella germanica, Periplaneta americana, and Periplaneta australasiae, 
especially the first two. These four domesticated species are easily sep- 
arated, being very distinctive in appearance, the two species of Periplaneta 
only offering any difficulty in this respect. But even their differentiation is 
easy by the figures and descriptive notes given herein, and by use of the 
following key, which is based upon easily appreciated characters. 

KEY TO THE FOUR PRINCIPAL HOUSEHOLD COCKROACHES 

1. Size small, total length usually no more than one-half inch; pronotal 
disk with two, longitudinal, parallel, blackish stripes ; last ventral 
segment of the abdomen of both sexes entire (fig. 7£). 

Blattella germanica (Linnaeus) Caudell. 

Size medium or large, rarely much less than one inch in length, usually 

more ; pronotal disk not marked as above ; last ventral segment of 

the abdomen of the male entire, of the female longitudinally 

divided — 2. 

9>. Size medium, length about one inch ; color black or dark brown, the 
pronotum unicolorous above; tegmina and wings abbreviated, in 
the male covering about two-thirds of the abdomen, in the female 
the tegmina forming mere lateral pads and the wings absent (fig. 
71). Blatta orientalis (Linnaeus). 

Size large, generally considerably more than an inch in length; color 
reddish brown, the pronotum above distinctly bordered with yel- 
lowish color; tegmina and wings fully developed in both sexes — 3. 

3. Tegmina with a yellowish, humeral stripe in distinct contrast to the 

color of the rest of the surface ; central dark area of the pronotal 

disk sharply outlined — Periplaneta australasiae (Fabricius). 

Tegmina not marked as above ; central area of pronotal disk less 

sharply outlined (fig. 73) Periplaneta americana (Linnaeus). 

Blatta orientalis (Linnaeus) (fig. 71) 

One of the most prevalent and widely distributed roaches is the Blatta 
orientalis of Linnaeus, in the Old World sometimes called the black beetle, 
a name now fortunately less used, for though it is black, the roach is 
not a beetle. The common name oriental roach is preferable for this 
species. 

Blatta orientalis is a medium sized roach of a blackish color. The 
male is an inch, or a little less, in length, of a very dark-brown color, and 
furnished with both tegmina and wings, covering about two-thirds of the 



COCKROACHES 



377 



abdomen, the tegmina often showing a reddish yellow cast. The female 
is noticeably larger than the male, of a more uniformly black color and 
provided with tegmina only, and these very short, being only about as 
long as the pronotum. In addition to the larger size and the shorter 
tegmina, the female can be readily distinguished from the male by the 
ventral surface of the terminal segment of the abdomen, which is plane 
in the male and divided longitudinally for its entire length in the female. 
This species is truly a gregarious insect, all stages living amicably 
together and often in incredible numbers where conditions are favorable 
for its occurrence. It is especially prevalent in cities, being, like the 




Fig. 71. — The Oriental roach, Blatta orientals: a, Female; b, male; c, side view of fe- 
male; d, half -grown specimen. All natural size. (Marlatt.) From U. S. Dept. 
Agr., Farmers' Bull. 658, figs. 1, 4. 

other domesticated species, less generally abundant in rural sections. It 
is a lover of warm, damp, unclean locations and often abounds in cheap 
restaurants and such places. The female may deposit a number of egg- 
cases a season, each containing about sixteen eggs, and breeding is con- 
tinuous when conditions of warmth, etc., are favorable. 



Blattella germanica (Linnaeus), Caudell (fig. 72) 

The German roach, or Croton bug, vies with the oriental roach in its 
importance as a household pest. It enjoys about as wide a distribution 
as its larger relative and in some sections it is the more important of the 
two. It is decidedly smaller than orientalis, the male being about one-half 
inch long and the female a little longer. The general color is yellowish 



378 



SANITARY ENTOMOLOGY 



brown with two, usually conspicuous, longitudinal, blackish stripes on 
the pronotum. Both sexes are fully winged, both tegmina and wings 
exceeding the tip of the abdomen in both sexes. The male is more slender 
than the female but the last abdominal segment does not exhibit sexual 
differences as in the case of the above species. It is a more active insect 
than orientalis, breeds faster, and is no less prevalent in houses, but, being 
less restricted to filthy surroundings, is more often found in houses of a 
better class. But no home, no matter how well kept, is immune from 
invasion now and then by one or more of these roaches, as not a store of 
food, bundle of laundry, or lot of supplies of any kind can be brought 
in without danger of one or more roaches being introduced. 

This species seldom occurs in company with the oriental roach, a house 
overrun with one species usually being free from the other. 




Fig. 72. — The German roach, Blattella germanica: a, First stage; b, second stage; c, 
third stage; d, fourth stage; e, adult; f, adult female with egg case; g, egg case, 
enlarged; h, adult with wings spread. All natural size except g. (From Riley.) 



Periplcmeta americana (Linnaeus) (fig. 73) 

This, the American roach, is less frequently abundant in houses than 
the smaller forms, at least usually so, though in the warmer parts of 
the world it is frequently the prevalent household species. It is more 
frequently reported as doing damage to plants in greenhouses, etc., and 
very often it creates havoc indoors with books, clothing, and other 
material. 

This roach is decidedly larger than either of the foregoing species, 
both sexes being about one and one-half inches in total length, often 
somewhat longer and rarely as much as a quarter of an inch shorter. 
Both sexes are fully winged, the wings usually surpassing somewhat the 
tip of the abdomen. The general color is reddish brown with the pro- 
notum generally bordered around the disk with lighter yellowish color, 
usually in distinct contrast to the darker central portion. The ventral 
surface of the last abdominal segment of the two sexes here differ as in 



COCKROACHES 



379 



the case of Blatta orientalis, being plane in the male and longitudinally 
divided in the female. 

This species is thoroughly cosmopolitan in distribution, having been 
recorded from almost every portion of the world except the colder regions. 
In some sections it is the most common house species, though in the east- 
ern United States it is not usually so common as either of the smaller 
species discussed above. 

As stated in the first part of this paper, the egg-cases of Periplaneta, 
the exact species not determined, are glued to various substances and 
covered over with particles chewed off by the insect. The egg-cases of 




Fig. 73. — The American roach, Periplaneta Americana: a, View from above; b, 
beneath. Enlarged one-third. (Marlatt.) 



from 



americana have been found, by actual count, to vary considerably in the 
number of eggs contained, the average, however, being about a score. 
The adult insect lives well over a year, one in captivity having died only 
after a confinement of one and one-third years. 

Nothing is inviolable to injury by this large roach, and it, as well as 
other forms discussed here, will even eat its own eggs, or a disabled indi- 
vidual of its own kind, to say nothing of other insects, even the ill- 
smelling bedbug. This species is often reported as damaging living plants, 
a thing seldom charged to the account of the smaller roaches. 

Periplaneta americana is the only one of our common house species 
indigenous to the New World, its original home probably being Tropical 
America. 



380 SANITARY ENTOMOLOGY 

Periplaneta australasiae (Fabricius) Burmeister 

This species is of the same general size and appearance as americana 
and has practically the same habits. It is readily distinguishable from 
that species by the elytra, which have an elongate yellowish spot bor- 
dering the outer margin next the pronotum. The yellowish margins of 
the pronotal disk is in greater contrast to the more clearly delineated 
central portion than in americana and the general size is also somewhat 
less. 

This roach is found mostly in warmer regions and is more often than 
any other species reported as injurious to plants in greenhouses, conserva- 
tories, etc. 

REMEDIES 

Remedies galore, good, bad, and indifferent, mostly the latter, have 
been recommended for use against roaches. No extended discussion of 
the divers methods proposed for the discouragement or destruction of 
these household pests will be here entered into. Only a few of the more 
promising methods of eradication will be considered. 

Fumigation 

Hydrocyanic Acid Gas 

In extreme infestation the best method of ridding a premise of 
roaches is by fumigation, the best fumigant being hydrocyanic acid gas 
at the rate of 10 ounces per 1,000 cubic feet for one hour. While thor- 
oughly effective, this treatment involves considerable cost, and, owing to 
its extremely dangerous qualities, necessitates extreme care in its appli- 
cation. Before attempting fumigation with this POISONOUS gas, de- 
tailed directions should be carefully studied. Such directions are given 
in the lecture on the control of human lice (p. 324). 

Carbon Bisulphide 

A fumigant less dangerous to use than the above, but one requiring 
much precaution because of its inflammability, is carbon bisulphide. This 
highly volatile material distributed in open vessels, one pound to each 
1,000 cubic feet of space, will destroy roaches, but the rooms fumigated 
must be ones that can be very tightly sealed up, as indeed must be the case 
in any fumigation. This method is well adapted for use in the holds of ships 
and other vessels. A fumigation of twenty-four hours will kill all vermin 
in a tightly sealed room. The violently explosive nature of this material 
necessitates extreme care in its use. No fire of any kind must be about 
when it is in use. 



COCKROACHES 381 

Pyrethrum Powder 

A safer, and sometimes as effective, fumigant is pyrethrum powder 
burned in infested quarters. The only precautions here needed is to see 
that the places under fumigation are tightly closed. 

Sulphur 

Fumigation for a period of six hours with fumes created by burning 
sulphur, four pounds per 1,000 cubic feet of space, is also recommended 
for the extermination of roaches. There are other substances possessing 
some value as fumigants but the above-mentioned materials comprise the 
most promising of them. 

Poisons 

In cases of moderate infestation, or occurrence in situations incon- 
venient for fumigation, some one of several substances poisonous to 
roaches can be employed. Our household species, however, especially 
the alert Croton bug, are not always easily persuaded to partake of 
poisoned food, as they appear to possess an uncanny knowledge of what 
materials are unhealthy for them to eat. In their ability to look out for 
themselves, and foil the attempts of man to destroy them, they have been 
compared to that wily bird, the crow. But in spite of their intelligence 
in avoiding pitfalls set in their way, they are more or less subject to 
control by various poisons and repellents. 

Sodium Fluoride 

This material has but recently come into prominence as a roach 
exterminator, but it is very surely the best remedy in the way of poisons 
now known. This powder probably kills both by contact and certainly 
as an internal poison, and by its use an infested apartment may be soon 
completely cleared of roaches. It is used either pure or diluted with one- 
half part flour or some other such substance. It is not injurious to man 
unless taken in considerable quantities and thus its use is not attended with 
danger. The powder is scattered about the haunts of roaches and blown 
into cracks and crannies occupied by them with a dust gun, or blower. 

Borax 

Powdered borax, used pure as a repellent, or mixed with some sub- 
stance attractive to roaches as a poison, is an effective remedy in many 
cases. One part of borax to three parts of pulverized chocolate is said 
to be a good mixture. 



382 SANITARY ENTOMOLOGY 

Pyrethrum Powder 

Dusting with pyrethrum powder is often recommended against roaches 
but experiments show that for the best results it should be used full 
strength. It is not to be compared with sodium fluoride in its effectiveness. 

Phosphorus 

A standard remedy for roaches, and one long in use, is phosphorus. 
This substance is used in the form of a paste composed of sweetened flour 
containing 1 or 2 per cent of phosphorus. This paste is spread on bits 
of cardboard and set about where it is easily accessible to the roaches. 

Sulphur 

Sulphur, in the powdered form, scattered about where roaches abound 
is said to be an effective repellent. 

Castor Oil 

One would scarcely expect this oil to be repellent to the omnivorous 
roach, but articles smeared with it are said to be rarely attacked by them. 

Of all the poisons and repellents mentioned above, sodium fluoride 
ranks the highest as an effective roach remedy. 

Traps 

Various sorts of traps have been recommended for catching roaches, 
but at the best such means only serve to lessen the numbers of roaches, 
probably never resulting in extermination. 

ENEMIES 

Certain hymenopterous parasites destroy the eggs of cockroaches and 
there are a number of predaceous insects and other enemies noted as feed- 
ing on the roaches themselves. The house centipede is recorded as killing 
the Croton bug and it is said that a toad or a tree frog will clear a room 
of roaches in one night. 



CHAPTER XXVII 

Diseases Transmitted by the Cockroach 
W. Dwight Pierce 

As cockroaches are so often found in houses and especially apt to 
frequent garbage and waste about a house, and frequent the food in the 
kitchen and on the table, it can readily be seen how easily they might 
transmit disease in case they are capable of carrying the organisms on 
their body or of retaining them in their systems. The cockroach feeds 
on filth of many kinds and goes straight from this filth to food.. As it 
feeds on the food it contaminates the same with its feces causing noxious 
odors which often ruin the food. We owe to Cao, the Italian investigator, 
our principal knowledge of the manner in which the cockroach can trans- 
mit disease organisms. Cao worked with the bacteria which might be 
found in food and in carcasses and he may be said to have covered the 
greater part of the bacterial organisms which the cockroach is most 
likely to be able to transmit. There can be no question of the desirability 
of controlling roaches in houses, hotels, and eating places. The necessity 
of this is the greatest in public eating houses where the roaches can feed 
on sputum and debris left by customers or by employees. A filthy em- 
ployee and a cockroach-infested restaurant make a combination to be 
feared. 

In the following pages will be found a summary of the records which 
have been made of the role of cockroaches in the transmission of organisms, 
especially disease organisms. 

PLANT ORGANISMS 

Thallophyta: Fungi: Coccaceae 

Micrococcus nigrofasciens Northrup, cause of an insect bacteriasis, 
has been experimentally transmitted to Periplaneta americana by North- 
rup. 

Sarcina alba Eisenberg has been isolated from the feces of Blatta 
orientalis by Cao in several series of experiments, but in no case was it 
found to be pathogenic after passage through the cockroach, even when 
fed in pure culture, or with other foods. In experiments with other 

383 



384 SANITARY ENTOMOLOGY 

insects, Cao has found this organism derived from the feces fatal to ani- 
mals (Cao 1906a). 

Sarcina aurantiaca Lindner and Koch. Cao (1906a) isolated this 
organism from the feces of Blatta orientalis, and found it nonpathogenic. 
In various experiments he fed it to roaches, finding that when fed in con- 
nection with a diet of bread and an infusion of putrid beef liver, a diet of 
bread and an infusion of 1 per cent peptone, and a diet of bread with 
a putrid infusion of beef flesh, it became slightly pathogenic after recov- 
ery from the feces of the roach. 

Sarcina lutea Schroeter was isolated by Cao (1906a) from the feces 
of Blatta orientalis and found nonpathogenic. In various experiments he 
fed it to roaches in connection with other foods, finding it nonpathogenic 
in all but four tests when it was given with infusion of putrid liver, pep- 
tone, or beef, in which cases it was slightly pathogenic after recovery from 
the feces of the roach. 

Staphylococcus pyogenes albus (Rosenbach) and S. p. aureus (Rosen- 
bach), the causes of many forms of SEPTICEMIA, have been proven by 
Herms to be capable of carriage by the Croton bug, Blattella germanica, 
on its feet, and he has shown that it can contaminate food on which it 
feeds, or with which it comes in contact, and also that both varieties can 
be found on the cockroach in nature. 

Tliallophyta: Fungi: Bacteriaceae 

Bacterium anthracis (Davaine), the cause of ANTHRAX, was fed by 
Kuster to Blatta orientalis and later recovered from its feces. 

Bacterium cholerae gallinarum (Perroncito), the cause of FOWL 
CHOLERA, was experimented with by Cao (1906a) in an attenuate form 
by feeding it to the cockroach Blatta orientalis. When fed to starved 
roaches without their food it passed through the intestines without an 
increase in virulence, but when fed to the roach in conjunction with a 
diet of bread with a putrid infusion of beef liver the organism partially 
regained its lost virulence. Kuster also fed this organism to B. orientalis 
and recovered it from the feces. 

Bacillus coli Escherich, a pathogenic organism normally found in the 
alimentary canal of man and animals, sometimes causing various types of 
diseases, has been isolated readily by Cao (1906a) from the feces of Blatta 
orientalis. He found that it remains in the intestines of the roach even 
after prolonged fasting. The various strains obtained varied in patho- 
genicity. When fed to the roaches in connection with other food it some- 
times greatly increased its virulence by passage through the insects. 

Bacillus fluorescens liquefasciens Fluegge, a fluorescent organism, was 
isolated by Cao from a series of Blatta orientalis, but he obtained no 



DISEASES TRANSMITTED BY THE COCKROACH 385 

pathogenic results from inoculations in this series. In another series of 
Blatta which had fasted for 45 days and whose feces contained no 
fluorescent bacilli and only a mildly pathogenic strain of Bacillus coli, he 
fed the roaches with this organism. One strain derived from the feces of 
a pigeon which had proven absolutely innocuous was fed to roaches for 
five days. The feces of the Blatta collected aseptically by squeezing the 
abdomen, killed a guinea pig in five days, with production of an abscess 
at the site of inoculation. From the pus was isolated a fluorescent bacillus 
which, when inoculated in pure culture subcutaneously, appeared patho- 
genic and killed a guinea pig and a cony in four and five days respec- 
tively, with production of a large purulence. Another strain isolated 
from an infusion of putrifying flesh was fed to three roaches and after 
eight days their feces were inoculated and killed a guinea pig in seven 
days, with production of an abscess at the site of inoculation. The 
fluorescent bacilli isolated from the feces were equally pathogenic. A 
third strain obtained from the air did not acquire perceptible virulence in 
passing through the roaches. A fourth strain isolated from earth in 
which were living many Lumbricus, acquired in the Blatta a notable patho- 
genicity. The feces contained germs which when isolated and inoculated 
killed a guinea pig in 54 hours with subcutaneous edema and slight enlarge- 
ment of the spleen, and exhibited its presence in the blood. He also con- 
ducted a considerable series of experiments in feeding this organism with 
other foods to the roaches, and demonstrated increased pathogenicity in 
many cases after recovering it from the feces. 

Bacillus fluorescens nonliquef asciens Eisenberg and Krueger was iso- 
lated by Cao in two series of experiments from the feces of Blatta 
orientalis and when inoculated into a guinea pig caused its death in 48 
hours without striking pathological symptoms, although the organism 
may be recovered from the blood. It was not so virulent in the cony, caus- 
ing death in eight days without purulence at the site of inoculation. When 
cultures of this organism were fed to starved Blatta one strain recovered 
from the feces of the guinea pig passed through the intestines of the 
roach remaining innocuous, but a strain isolated from the earth had a 
moderate pathogenicity in the Blatta, producing abscess and death of 
a guinea pig; the inoculation of pure culture killing a guinea pig in four 
days, with production of a large subcutaneous abscess. The germs were 
recovered from the spleen and from the pus. Quite a series of experiments 
were conducted with three strains of this bacillus, feeding them in con- 
nection with other foods, and in a number of these experiments two of 
the strains became moderately pathogenic. 

Bacillus megatherium Ravenel, a chromogenic organism found in soil, 
was isolated by Cao from the feces of a Blatta orientalis in a single series 
of experiments. In all of his experiments with this organism lie did not 



386 SANITARY ENTOMOLOGY 

find that it acquired pathogenicity by passage through the intestines of 
the insect with or without other foods. 

Bacillus "proteisimile" Cao. An organism virtually described under 
this name was isolated by Cao from the feces of Blatta orientalis in two or 
more series of experiments in three different strains of varying virulence. 
One strain retained its virulence in successive passages for five months. In 
two experiments in which starved cockroaches with nonpathogenic feces 
were fed on nonvirulent cultures of this germ and on a diet of bread 
with putrid infusion of beef liver, and on a diet of 1 per cent infusion 
of peptone, this germ became intensely pathogenic in the first case, killing, 
when inoculated, a guinea pig in two or three days, and in the second case 
in 36 to 40 hours, with acute septicemia. 

Bacillus "pseudo edema maligno" Cao, cause of MALIGNANT 
PSEUDOEDEMA, was isolated by Cao in one instance from a series of 
B. orientalis, and he found it retaining its virulence in successive passages 
through many months. 

Bacillus radiciformis TatarofF, a saprophytic organism found in water, 
was isolated by Cao from the feces of Blatta orientalis in a single series 
of experiments. In all of his tests with this organism, he did not find 
that it acquired pathogenicity by passage through the intestines of the 
insect with or without other foods. 

Bacillus " simile arbonchio" Cao, an organism described by Cao as simi- 
lar to B. anthracis, was isolated in pathogenic strains from Blatta 
orientalis by Cao. In one series of experiments it was isolated from a 
number of B. orientalis, the feces of which, when inoculated into a guinea 
pig, caused its death in 42 hours. From pure cultures isolated from the 
feces, it was inoculated into a guinea pig and caused its death in 40 hours, 
with intense sero-sanguinolent edema and an enormous spleen. The organ- 
ism was recovered from the heart blood. A cony inoculated with pure 
culture died in 48 hours, with symptoms similar to those found in hematic 
carbuncle. The germs were still found in the feces of the cockroaches 
after 21 days fasting and retained their virulence, causing death with 
formation of a tumor on the spleen, but less intense. It maintained its 
virulence in successive passages through many months. When fed to 
starved cockroaches with nonpathogenic feces, two nonpathogenic strains 
(one from soil and one from the feces of Calliphora vomitoria) failed to 
increase their pathogenicity when eaten alone, or when combined with 
sterile bread, sour milk, putrid milk, rotten egg, and fresh flesh; but one 
strain obtained slight pathogenicity when eaten with putrid flesh, moderate 
pathogenicity when combined with human feces, and intense pathogenicity 
when eaten with a diet of bread and putrid beef liver, a diet of bread 
and 1 per cent infusion of peptone, or a diet of bread and an infusion of 
putrid beef flesh. 



DISEASES TRANSMITTED BY THE COCKROACH 38? 

Bacillus subtilis Ehrenberg, an organism frequently found in air, 
water, and soil, seldom pathogenic, was fed in three series of experiments, 
by Cao, in conjunction with other foods to starved roaches of Blatta 
orient alls. In two cases he obtained slight pathogenicity inducing local 
suppurations but no killing of the experimental host. 

Bacillus "tifosimUe" Cao, a bacillus described by Cao resembling B. 
typhosus, was isolated by Cao in three out of four series of experiments 
from the feces of B. orientalis in strains of varying virulence, which could 
in some cases be increased by feeding to the cockroaches in connection 
with other foods. 

Bacillus tuberculosis Koch, the cause of TUBERCULOSIS, was fed 
by Kiister to Blatta orientalis and later recovered from its feces. 

Bacillus typhosus Eberth, the cause of TYPHOID FEVER, is con- 
sidered by Herms and Nelson, and also by Longfellow, as capable of being 
transmitted bv the cockroach. 



Thallophyta: Fungi: SpirUlaceae 

Spirillum cholerae Koch, the cause of ASIATIC CHOLERA, can be 
carried by cockroaches as demonstrated by Barber in the Philippines. He 
fed Periplaneta americana on human feces infected with the cholera 
vibrios and these roaches passed living vibrios in their feces up to 79 
hours, and when fed on cholera cultures, up to 24 hours. Active, motile, 
cholera vibrios often appeared in enormous numbers in the insects' feces. 
A cockroach was also observed to disgorge portions of its meals at inter- 
vals of ten, twenty, and sixty minutes after feeding, sufficient time for it 
to travel from the closet to the human food. The sixty minute sample 
contained many cholera vibrios. No vibrios were found in the salivary 
discharge of the insect. 

Spirillum metchniJcovi (Gamaleia). This organism, cause of a FOWL 
DIARRHEA, was experimented with by Cao, who determined that Blatta 
orientalis which had not fed for 45 days and of which the feces only con- 
tained a mild strain of Bacillus coli, when fed on a feeble strain of this 
organism, passed it through its feces deprived of its pathogenicity. He 
fed cultures of the organism at the same time with sterile bread and also 
with fresh flesh with the same result ; but when cultures of this feeble 
strain were fed in connection with a diet of bread and an infusion of 
putrid beef liver, a diet of bread and a 1 per cent infusion of putrid 
peptone, and a diet of bread and an infusion of putrid beef liver, they 
regained intense pathogenicity. 



388 SANITARY ENTOMOLOGY 

ANIMAL ORGANISMS 

Protozoa 

Sarcodina: Amoebina: Amoebidae 

Endamoeba blattae (Biitschli) passes both its sexual and asevual 
cycles in the intestines of Blatta orient alls. 

Mastigophora: Polymastigma: Tetramitidae 
Trichomonas orthopterum Parisi is parasitic in Blatta species. 

Mastigophora: Binucleata: Leptomonidae 

Leptomonas blattarum (Stein) is parasitic in endoderm of Blatta 
orient alis. 

Telosporidia: Gregarmida: Gregarinidae 

Clepsidrma blattarum Von Siebold is a parasite in the intestine of 
Periplaneta americana. 

Clepsidrina serpentula DeMagalhaes is also a parasite in the intestine 
of Periplaneta americana. 

Gamocystis tenax Schneider is a parasite in the intestine of Blattella 
lapponica. 

Gregarina legeri Pinto is a parasite in the intestine of Periplaneta 
americana. 

Gregarina blattarum Von Siebold is a parasite in the intestine of 
Blatta orientalis, Periplaneta americana and Blattella germanica. 

Telosporidia: Coccidiidea: Eimeriidae 

Diplocystis schneideri Kiinstler is a parasite in Periplaneta ameri* 
cana. 

Neosporidia: Myxosporidia: Thelohaniidae 

Plistophora periplaneta Lutz and Splendore is parasitic in Blatta 
orientalis and Periplaneta americana. 

Plistophora sp. causes neoplasia of the adipose tissue in Blatta 
orientalis. 

Ciliata: Heterotricha: Bursarinidae 
Nyctotherus ovalis is parasitic in the intestine of Blatta orientalis. 



DISEASES TRANSMITTED BY THE COCKROACH 389 

Metazoa 

Platyhelmia: Cestoidea: Hymenolepididae 

Davainea madagascariensis (Davaine) is a tapeworm of man of which 
the life history is unknown but Castellani and Chalmers suggest that 
the cysticercus may be found in the cockroaches Blatta orientalis and 
Periplaneta americana. 

Nemathelminthes : Acanthocephala: Gigantorhynchidae 

Moniliformis moniliformis (Bremser), a parasite of rodents and 
occasionally of man, may pass its larval stage in Periplaneta americana, 
according to De Magalhaes. 

Nemathelminthes : Nematoda: Spiruridae 

A larval nematode, evidently one of the Spiruridae, is described from 
the visceral cavity of Periplaneta americana by De Magalhaes, 

Gongylonema pulchrum Molin is a parasite of the hog. Ransom and 
Hall report feeding eggs of a Gongylonema of the hog, presumably 
of this species, to Croton bugs, Blattella germanica, and finding that the 
eggs hatched and developed to encysted larvae. 

Gongylonema neoplasticum (Fibiger and Ditlevson), a human para- 
sitic worm which produces cancer-like tumors in the stomach of the rat, 
passes its intermediate stages in Blattella germanica and Blatta orientalis. 
It develops as far as an encapsuled larva in the cockroach, according to 
Fibiger and Ditlevson. 

Gongylonema scut at um (Muller), a verycdppmmon parasite of cattle, 
can pass its first stages in the cockroach Blattella germanica, under 
experimental conditions, according to Ransom and Hall. 

Spirura gastrophila (Muller), a parasite in the alimentary canal of 
the hedgehog, has been found by Seurat in the fourth stage encapsuled 
in the general cavity of Blatta orientalis. 

Nemathelminthes : Nematoda: Oxyuridae 

Oxyuris blattaorientalis Hammerschmidt is found in the cockroaches 
Blatta orientalis and Periplaneta americana according to De Magal- 
haes. 

Oxyuris bulhoesi De Magalhaes is also found in the intestine of 
Periplaneta americana according to De Magalhaes. 

Oxyuris diesingi Hammerschmidt is found, according to De Magal- 
haes in Blatta orientalis and Periplaneta americana. 



390 SANITARY ENTOMOLOGY 

Oxyuris hunckeli Galeb is, according to De Magalhaes, found in 
Periplaneta americana. 

It will be seen by the evidence presented that the cockroach is a 
potential carrier of many disease organisms, but, however, it has not yet 
been proven to be definitely a regular carrier of many. Those diseases 
which you can most surely expect to be transmitted from time to. time by 
cockroaches are those in which the organism can be taken up from the 
feces of man or animals and carried by the roaches to food. 

You can also see that the danger from cockroach transmission of 
diseases is in small towns where there is little care about sanitation, and 
where there is no sanitary sewerage. Any one who has traveled exten- 
sively in the small towns of America can readily see how cockroaches could 
transmit diseases by polluting food in hotel kitchens and even dining 
rooms, and even by polluting the bread and food in the grocery stores 
and meat markets. 

No one has really made a consistent study of the possibilities of cock- 
roach transmission of diseases and there is very little doubt that, if such 
studies could be conducted in a locality where disease transmission is pos- 
sible, much evidence against the roach could be obtained. 

REFERENCES 

Barber, M. A., 1914. — Philippine Journ. Science, Manila, vol. 9 B, No. 1, 
pp. 1-4. 

Cao, G., 1906a.— Annali D'Igiene Sper., vol. 16, n. s., pp. 339-368. 

De Magalhaes, P. S., 1900.— Arch, de Parasit., vol. 3, p. 45-69. 

Fibiger, J., and Ditlevson, H., 1914. — Anat. Path. Inst, and Zool. Mus. 
Univ. Copenhagen, vol. 25, 28 pp., 4 pits. 

Herms, W. B., 1915. — Medical and Veterinary Entomology, pp. 41-43. 

Herms and Nelson, 1913. — Am. Journ. Pub. Health, September. 

Kiister, H. A., 1902. — Inaugural Dissertation Doctorwiirde Univ. Heidel- 
berg, 43 pp. 

Longfellow, R. C, 1913. — Am. Journ. Pub. Health, January, p. 58. 

Northrup, Z., 1913.— Michigan Agr. Exp. Sta., Tech. Bull. 18, 32 pp. 

Ransom, B. H., and Hall, M. C, 1915. — Journ. Parasitol.,.vol. 2, No. 2, 
pp. 80-86. 

Seurat, L. G., 1916. — Bull. Scient. France et Belgique, ser. 7, vol. 49, 
fasc. 4, pp. 310-314, 350. 



CHAPTER XXVIII 

The Bedbug and Other Bloodsucking Bugs: Diseases Transmitted. 

Biology and Control x 

TT. DiCight Pierce 

Probably no species of bloodsucking insect is better known through- 
out all the world than the bedbug. Cimex lecttdarius Linnaeus. This 
species and its congener. C. liemlpterus Fabricius (rotundatus) Signoret, 
live in the beds of man and suck human blood. There are a number of 
related species, among which C. boueti Brumpt. in French Guinea, is also 
said to suck the blood of man. The other species are bird and bat para- 
sites. 

Oh account of the habit of the bedbug of sucking the blood of man, 
but hiding by day in houses and vehicles, this species has many oppor- 
tunities of transmitting diseases, provided that its methods of life con- 
form with the requirements of the disease organisms. Girault has pointed 
out that the bedbug will feed on mice, living or dead. This is a very 
important point in considering its ability to transmit disease. 

Any disease which should be shown to be spread exclusively by the 
bedbug will undoubtedly have a localized distribution, and 'is very likely 
to be confined to certain buildings or groups of buildings, but on the 
other hand may be spread long distances by travelers carrying the 
bugs in their baggage and on their clothes. It will never be possible 
for a disease carried by bedbugs to spread rapidly like a fly-borne oi 
mosquito-borne disease. As bedbugs have been found in houses without 
human occupants for two years or more, we must a-sume that they obtain 
blood from rodents, and it is possible that in this way an infection might 
be maintained in a dwelling. There is some very interesting literature on 
the possible disease-transmitting role of bedbugs and this has been briefed 
and arranged below in the same manner that the discussions of diseases 
transmitted by other insects have been arranged in preceding lectures. 
Certain other blood-sucking bugs are included in the discussion. 

J This lecture was presented November 18, 1918, and distributed January -25, 1919. 

391 



392 SANITARY ENTOMOLOGY 



DISEASES OF THE PLANT KINGDOM TRANSMITTED BY BUGS 

Thallophyta: Fungi: Bacteriaceae 

Bacillus leprae Hanson, the cause of LEPROSY, has been considerably 
experimented upon with a view to determining the possibility of bedbug 
transmission. Carmichael, in 1899, suggested the possible connection 
between bedbugs and leprosy. Long, in 1911, conducted experiments. 
He allowed two bedbugs to bite lepers, in the neighborhood of leprous 
nodules, and then examined the alimentary canal of the bugs and found 
them to contain the bacilli. He cites in one of his papers the case of a 
certain man who slept in a hut formerly occupied by a leper. He was 
bitten by bugs while sleeping there and later developed the disease. Skel- 
ton and Parham think transmission by bedbugs in Zanzibar to be im- 
probable. Thomson has conducted a few experiments with this organism, 
and Smith, Lynch, and Rivas have also published an article on the trans- 
missibility of the leper bacillus by the bedbug. Ehlers found the leprosy 
bacillus in the digestive tract of bedbugs in the West Indies in 1909 (see 
Cumston 1918). Sanders in South Africa found the bacillus in 20 out 
of 75 bugs fed, when starved, on leprous patients. The bacilli occurred in 
the proboscis up to the fifth day, in the digestive tube to the sixteenth 
day, and also in the feces. Goodhue also found the lepra bacillus in bugs 
which have bitten leprous patients. It still is incumbent upon some one 
to attempt the transmission of the leper bacillus by inoculation of feces 
of the bedbug in skin abrasions. It would appear that scratching after a 
bite would be the logical means of inoculating the disease. 

Bacillus pestis Kitasato, the cause of BUBONIC PLAGUE, has been 
experimented on by a number of authors to determine the possibility of 
transmission by bedbugs. Vubitski conducted certain experiments which 
are reviewed by Manning. Cornwall and Menon have also written on 
the possibility of transmission of plague by bedbugs. 

Cumston (1918) reviews the literature, but signally fails to grasp the 
significance of the records he quotes. Like most other investigators he 
was looking primarily for evidence of transmission by bite. Jordansky 
and Klodnitzky succeeded in inoculating mice with plague by having them 
bitten by infected bedbugs. They found large numbers of plague bacilli 
in the digestive tube of one bedbug and a few in another on the 36th day 
after they had bitten a pestiferous mouse. Nuttall and Wierzbitzky also 
found the bacillus in the digestive tube. In India Walker found 22% of 
the bugs in huts of natives infected with plague, to be infected with the 
bacillus. He also transmitted the plague to a rat by a bug which had 
bitten a pestiferous patient. 



THE BEDBUG AND OTHER BLOODSUCKING BUGS 393 

Bacillus typhosus Eberth, cause of TYPHOID FEVER, may possibly 
be transmitted by the bedbug, according to Riggs. 



DISEASES OF UNKNOWN ORIGIN 

POLIOMYELITIS or INFANTILE PARALYSIS has been sus- 
pected by various authors of being insect-transmitted. Manning has 
made a contribution to the study of the possible agency of the bedbug 
in the transmission of this disease and claims that the bedbug fulfills 
the necessary requirements as a carrier of this disease. Howard and 
Clark (1912) obtained definite experimental evidence of the possibility of 
the bedbug as a carrier. In one out of several experiments, ten bed- 
bugs fed on a patient took up the virus and when, seven days later, 
these were killed, ground up in salt solution, filtered, and injected, the 
monkey became paralyzed and an autopsy showed typical lesions. A 
second monkey inoculated from this one developed a definite paralysis on 
the 6th day and an autopsy showed characteristic lesions. 



DISEASES OF THE ANIMAL KINGDOM TRANSMITTED BY BUGS 

Protozoa 
Mastigophora: Binucleata: Trypanosomidae 

Castellanella brucei (Plimmer and Bradford) Chalmers (Trypano- 
soma), the cause of NAGANA of animals, and probably identical with 
the causative organism of SLEEPING SICKNESS, was experimentally 
transmitted, according to Sangiorgi, to white mice by the bite of Cimex 
lectularius. This organism is normally transmitted by tsetse flies and 
horse flies. 

Castellanella equinum (Voges) (Trypanosoma) the cause of MAL 
DE CADERAS, a South American disease of horses, of which the wild 
animal reservoir is probably the capybara, is probably transmitted by 
the kissing bug, Triatoma infestans, but Sangiorgi succeeded in trans- 
mitting it to white mice by the bite of Cimex lectularius. 

Schizotrypanum cruzi Chagas (Trypanosoma) the cause of CHAGAS 
FEVER, a disease of man in South America, is carried by sucking bugs. 
The disease has its reservoir in the armadillo and related animals. Chagas 
and Brumpt have proven that the natural invertebrate hosts are the 
kissing bugs Triatoma megista Burmeister, T. sordida Stfil, T. geniculata 
Latreille, and T. chagasi, and, undoubtedly also Rhodnius prolixus Stal. 
Gonzales-Lugo has obtained experimental transmission with the last 



394 SANITARY ENTOMOLOGY 

named bug and Brumpt has proven it a durable host. Brumpt has also 
demonstrated development in the bedbugs Cimex lectulariws, C. boueti, 
and C. hemipterus. 

There are two types of reproduction of the organism in the insects. 
In the sexual method, about six hours after ingestion of blood the kineto- 
nucleus moves close to the trophonucleus with which it possibly blends; 
the flagellum and undulating membrane are now usually lost, but some 
forms retain the flagellum. The parasite becomes rounded and multiplies 
repeatedly by division. After this has ceased it becomes pear-shaped, 
develops a flagellum and becomes a crithidial form and then passes into 
the cylindrical portion of the intestine where it can be seen in about 25 
hours after the ingestion of blood. The final stage is a small, trypaniform 
type, long and slim with band-like trophonucleus and large kinetonucleus. 
This form is found in the hind gut in the body cavity and in the salivary 
glands, and is the form by which the parasite is transmitted to a new ver- 
tebrate host. The development in the bug requires at least eight days 
for its completion. 

The asexual method of reproduction is a constant process and is a 
simple multiplication, giving rise to the crithidial forms which are found 
principally in the hind gut. 

Originally the disease was supposed to be transmitted by the sucking 
of blood by insects. Brumpt declares that transmission is exclusively 
by dejections. As Rhodnius prolixus passes its dejections immediately 
after removing its beak, while the Triatoma species do not pass dejections, 
during their repast, Brumpt thinks it likely that Rhodnius is a more 
potent transmitter, in view of the fact that dejections are infective. In 
this connection the bedbug has a very interesting habit which bears upon 
the possibility of its transmitting the disease. Patton and Cragg have 
pointed out that it defecates immediately after a feed, but unlike the 
majority of bloodsucking insects, does not pass out red blood, but only 
the remains of the last meal, a semi-solid sticky material. This black 
fluid is passed out just after the proboscis is withdrawn, and the bug 
has a very characteristic habit of turning around and moving back- 
wards in such a way that the excreta fall in the neighborhood of the 
wound made by the proboscis. Blacklock has studied the multiplication 
and infectivity of S. cruzi in Cimex lectularius, and concludes that the 
organism is capable of living and multiplying in the bedbug for long 
periods. The parasites found in the bedbug are infective on inoculation 
as early as 21 hours and as late as 77 days from the infecting feed. 
Transmission of the disease to healthy animals by feeding an infected 
bug on them is of very rare occurrence. It was only once observed in the 
course of these experiments. In the light of Brumpt's work, we can now 
see that feeding experiments were almost naturally to be expected not to 



THE BEDBUG AND OTHER BLOODSUCKING BUGS 395 

succeed, as the transmission of the disease is apparently only by con- 
tamination through scratching in or inoculation of infected feces. 

Trypanozoon duttoni (Thiroux) (Trypanosoma), an organism 
usually found in mice, has been shown by Brumpt to be capable of de- 
veloping in Cimex lectularius. It is usually parasitic in fleas and is 
transmitted to the mice by their licking up the feces of the fleas or the 
fleas themselves. It is probably infective by means of bedbugs in the 
same manner. 

Trypanozoon lewisi (Kent) (Trypanosoma), the cause of RAT 
TRYPANOSOMIASIS, is usually carried by fleas, but Brumpt (1913a) 
finds that it can complete its cyclical development in Cimex lectularius, 
and he infected a rat with an inoculation of the rectal contents of a bug 
after six days and also after 38 days. 

Trypanosoma (sens, lat.) vespertilionis Battaglia, the cause of BAT 
TRYPANOSOMIASIS, is transmitted by the bat bedbug, Cimex pipis- 
trelli Jenyns, according to Pringault. 

Mastigophora: Binucleata: Leptomonidx 

Leishmania species, the cause of NON-ULCERATING ORIENTAL 
SORE, passes part of its life cycle in the bug, Erthesina fullo (Thun- 
berg), according to Carter. 

Leishmania donovani (Laveran and Mesnil), the cause of INDIAN 
KALA AZAR, has been thought by many to be transmitted by insects. 
There is considerable conflicting evidence on the subject, a greater part 
of which is reviewed very thoroughly by Wenyon. Patton has demon- 
strated the development of the organism in the bedbugs Cimex hemipterus 
(rotund atus) and C. lectularius in India. Cornwall and La Frenais fed 
Cimex hemipterus on citrated rabbit blood containing this organism, 
through a membrane, and obtained infection of the bugs and development 
of the parasites for a period of at least 29 days. Cornwall and Menon 
having shown in previous papers that the bedbug can not regurgitate 
the contents of its stomach in the act of feeding and therefore can not 
transmit kala azar or Oriental sore by its bite, and being unable to find 
evidence of any intracellular stage of the parasite in the bug, turned 
their attention to the contents of the rectum. No one has been able to 
demonstrate the presence of any resistant stage in the feces of the bugs, 
although these authors have found active flagellates, and occasionally 
rounded forms, as far down as the lower intestines of the infected bugs, 
in a fairly large proportion of those examined. They failed to find any 
form which could suggest an extra corporeal resistant stage. They 
have found active flagellates in the stomach contents of the bugs for 29 
days. 



396 



SANITARY ENTOMOLOGY 



r 1 •■ ft 



1 



<& 




Fig. 74. — Bedbug: Egg and newly hatched larva: a, Larva from below; b, larva from 
above; c, claw; d, egg; e, hair or spine of larva. Greatly enlarged, natural size of 
larva and egg indicated by hair lines. (Marlatt.) 




Fig. 75. — Bedbug: a, Larval skin shed at first molt; b, second larval stage immediately 
after emerging from a; c, same after first meal, distended with blood. Greatly 
enlarged. (Marlatt.) 



The life cycle in Cimex hemipterus and C. lectularius has been dem- 
onstrated by Patton. The parasites are ingested by the bug, enclosed in 
the large cells or leucocytes, and develop into fully flagellated forms 
without reference to the temperature of the external air. The size 
increases from 4 to 7 micra and vacuolation of the cytoplasm occurs on 
or after the second day. The single parasite may proceed directly to 
flagellation, by the appearance of an area stained bright pink by Giemsa 
solution and called the flagellar vacuole. This vacuole which has a dark 
center rapidly increases in size up to 1 to S micra and, passing to the 
surface, sends out a pink brush which forms the flagellum by merely 
growing longer. The flagellate form has a dark blue, granular cytoplasm 
with a circular trophonucleus which stains deeply in the center; and a 
kinetonucleus lying across the long diameter and situated near the 



THE BEDBUG AND OTHER BLOODSUCKING BUGS 397 




Fig. 76. — Bedbug: Adult before engorgement. Much enlarged. (Marlatt.) 




Fig. 77. — Bedbug, Cimex lectularius : a, Adult female, engorged with blood; b, same from 
below; c, rudimentary wing pad; d, mouth parts, a, b, Much enlarged; c, d, highly 
magnified. '(Marlatt.) 

(All from U. S. Dept. Agr. Farmers' Bull. 754, figs. 3, 4, 2, 1.) 

trophonucleus, and possesses a long flagellum consisting of a number 
of filaments adhering closely together, inserted into a pale area near the 
kinetonucleus. These parasites may divide into two equal flagellate forms 
and apparently may go on dividing for some time. Instead of proceeding 
directly to flagellation, the parasite may show a division of its nuclei into 
two, with the formation of two flagella, and then division into two 
flagellate parasites, or the nuclei may multiply without division of the 
cytoplasm, so that forms containing four to eight nuclei may be to- 
gether, which eventually break up into separate flagellate forms. If the 
bug feeds on blood before the development is completed, the flagellates 
are destroyed. Development is completed in ten to twelve days after a 
single feed. 

Cornwall and La Frenais describe a thick-tailed form in the bug 
after the 20th day. Cornwall and Menon state that the flagellate form 



398 SANITARY ENTOMOLOGY 

thrives only at temperatures from 16° to 26° C. (61° to 79° F.) and 
is therefore unfitted to exist in the human body. This is further evidence 
that the flagellate is a typical insect form. They have failed to find a 
postflagellate cystic form in the stomach of the bug. 

Transmission by insects has not been demonstrated, although there is 
considerable evidence that it can not be transmitted by the bite of the 
bedbug in which the organism normally flagellates. Cornwall and Menon 
claim that there are only two possible means of transmission left ; rupture 
of a bug containing flagellates in the neighborhood of a puncture or 
abrasion, and passage of cystic forms into the feces, and there is no 
direct evidence for either. They lean to the rupture theory because it 
seems to account for the peculiar distribution of kala azar. It is com- 
paratively rare and often localized in certain dwellings. The bug does 
not live on the person, but in buildings and furniture. It does not gener- 
ally crawl over the skin when feeding but attacks exposed parts from a 
fairly safe position. It must therefore be a comparatively rare event for 
a bug to be ruptured on the skin of its occasional host. They may be 
transported from place to place in furniture and clothing, and may go 
from house to house in search of food. The bug is also more or less 
localized. As the bug would be sacrificed in the act of transmission, it is 
clear that a human reservoir of the disease must be at hand if the bugs in 
a building are to remain dangerous. Knowles suggests the possibility 
of hereditary transmission in the bedbug or in intestinal worms. 

Leishmania tropica (Wright), the cause of ORIENTAL SORE, is 
also thought to be transmitted by insects. Wenyon found that the bed- 
bug Cimex lectularius could take up the parasites and that develop- 
mental stages were demonstrable in its gut. Patton (1912) obtained 
development of the parasite into flagellate forms in Cimex Jiemipterus at 
low temperature (2£° to 25° C.) and produces considerable evidence 
in favor of these species as the natural carrier. 



Mastigophora: Spirochaetacea: Spirochaetidae 

Spiroschaudinnia berbera (Sergent and Foley), the cause of NORTH 
AFRICAN RELAPSING FEVER, is spread by the body louse. Sergent 
and Foley have obtained negative results with Cimex lectularius. 

Spiroschaudinnia duttoni (Novy and Knapp), the cause of TROP- 
ICAL AFRICAN RELAPSING FEVER, is normally spread by ticks. 
Breinl, Kinghorn and Todd in 1906 and Nuttall in 1907, were unsuc- 
cessful with transmission experiments with Cimex lectularius, 

Spiroschaudinnia recurrentis (Lebert), the cause of EUROPEAN 
RELAPSING FEVER, is normally transmitted probably by the body 



THE BEDBUG AND OTHER BLOODSUCKING BUGS 399 

louse. Nuttall in 1907 experimented with the Russian strain of this 
disease and succeeded in transmitting relapsing fever, in one experiment, 
to a mouse by the bite of Cimex lectularius. He found that usually the 
spirochaetes were digested by the bugs, the time depending upon the tem- 
perature. Fliigge, in 1897, infected monkeys with the contents of bugs, 
removed twenty-four hours after they had fed on relapsing fever blood. 
Karlinski and also Schaudinn observed the survival of spirochaetes in 
two bugs for 30 days or more. Various authors have failed to transmit 
spirochaetes by bugs, but it is probable that these failures were because 
they attempted to transmit by means of the bite, rather than by crushing 
or scratching in the contents of a bug or its feces. Tictin, however, 
while suggesting that the bedbugs might transmit the disease by their 
bite, also suggested that it might be by their being crushed and the 
contents entering the skin through excoriations due to scratching. 

In summary we may draw the conclusion that probably all disease 
organisms which are capable of passing part of their cycle in the bed- 
bug will be found to be transmitted through the scratching in of the 
feces of the bug, or by the rupturing of a bug while in the act of feeding, 
or over an excoriation of the skin. It is quite possible that any organism 
which the bug may take up from the blood and which in like manner 
is infective to the blood can be transmitted under favorable conditions in 
this manner. 

There is most certainly a very promising field for research in the 
working out of the possibilities of disease transmission by blood-sucking 
bugs. 

LIFE HISTORY NOTES 

This lecture deals primarily with the bedbugs of the genus Cimex, 
family Cimicidae, but also contains mention of the false bedbugs, or 
kissing bugs of the genus Triatoma (Conorhinus), family Reduviidae. 

The best discussion in English, with illustrations, of the genus 
Triatoma {Conorhinus) is given by Patton and Cragg. These bugs live 
on human and mammalian blood. The egg of Triatoma rubrofasciata 
(De Geer) of India is rounded at one end and flattened at the other, 
which forms a kind of operculum. It measures 2 mm. by 1 mm. The 
incubation period varies from 20 to 30 days. The development is similar 
to that of all winged Reduviids, each stage showing more developed wing 
pads, until the fully winged adult stage is reached. The development 
requires several months from eggs to adult. 

Triatoma megista (Burmeister) of South America is almost entirely a 
domestic insect. The adults enter inhabited houses, but never those which 
have been abandoned. In old houses thev are to be found in cracks and 



400 SANITARY ENTOMOLOGY 

holes in the walls, where they lay their eggs. The early stages, which are 
wingless, crawl out of their resting places in the walls as soon as the 
lights are put out, and make their way to the beds of the occupants of 
the house. The adults behave in the same manner, but as they are pow- 
erful fliers they can reach people who sleep in hammocks. The bite is said 
to be painless and to leave no mark; this is quite unlike the bite of 
Triatoma rubrofasciata, which, in the case of some people, leaves a dis- 
tinct mark for weeks. The eggs of T. megista are laid in batches of from 
8 to 12, and as many as 45 such batches may be laid. They hatch in from 
25 to 50 days. A generation requires about 324 days. 

Triatoma sanguisuga (Le Conte) is a native of the United States 
and is called the Texas bedbug, or the "blood-sucking cone nose." It 
comes into the houses and sucks the blood of man. It is also found in 
chicken houses and horse stalls, but its normal food is supposed to be the 
body juices of other insects, including the bedbug. 

A number of other species are recorded as causing severe bites on 
man. 

The bedbugs Cimex lectularius Linnaeus, C. hemipterus Fabricius 
(rotundatus Signoret), and C. boueti Brumpt, attack man, while C. hirun- 
dinis Jenyns attacks the swallow, C. columbarius Jenyns the pigeon, and 
C. pipistrelli Jenyns the bat. The first named is cosmopolitan, the second 
tropical and subtropical, the third South American. The first two are 
essentially domestic species. During the daytime these species hide in 
cracks and crevices in the beds, furniture, and walls of bedrooms. They 
usually feed at night but will not uncommonly feed in the daytime if they 
can do so without detection. The most characteristic feature of the bed- 
bug is the very distinct and disagreeable odor which it exhales. The 
absence of wings in the bedbug is of great advantage in control work, 
as it confines its range to those points it can reach in its roaming. The 
eggs are white, oval objects having a little projection run around one 
edge, and may be found in batches of from 6 to 50 in cracks and 
crevices where the parent bugs go for concealment. A single female may 
lay as many as 190 eggs. The eggs hatch in a week or ten days in warm 
weather, but require a considerably longer time in cold weather. The 
young are yellowish white at first, but in succeeding molts become darker 
and darker brown. There is very little important difference in the 
appearance of nymphal and adult stages. There are five molts covering 
varying lengths of seven to eleven or more weeks. The bedbug is capable 
of living for long periods without food. Normally fed bugs may live 
almost a year, and partly grown specimens have been kept 60 days 
without food. The bite of the bedbug is very poisonous to some per- 
sons, and their presence is sufficient to cause uneasiness and loss of 
sleep. (Figs. 74-77.) 



THE BEDBUG AND OTHER BLOODSUCKING BUGS 401 

Hcemato siphon modora Duges is a native American bug related to 
the bedbug, found in the Southwestern States and Mexico. It was 
probably originally a parasitic messmate of birds and bats, but has now 
become an important poultry pest, and in those regions, due to the close 
associations between poultry and human beings, is often a serious house 
pest. 

TREATMENT OF BITES 

To allay the irritation caused by the bite of the bedbug peroxide 
of hydrogen, or dioxygen, may be used with good results. 
Tincture of iodine is also a good counterirritant. 

CONTROL MEASURES 

There is practically no information on adequate methods of con- 
trolling the Triatomas. 

The bedbug when badly infesting houses may be controlled by fumi- 
gation with hydrocyanic acid gas at the rate of 10 ounces of cyanide for 
each 1,000 cubic feet, or fumes of sulphur at the rate of five pounds per 
1,000 cubic feet. Such fumigation should be carried out as described 
elsewhere (p. 325). 

In cases of moderate infestation it is possible at a slightly greater 
cost of time and personal effort, to eradicate the bugs by a liberal 
use of benzine or kerosene, introduced with small brushes or feathers, or 
by injecting with syringes into all crevices of beds, furniture, or walls 
where the insects may have concealed themselves. 

Corrosive sublimate and also oil of turpentine may be used in the 
same way. 

Careful inspection of beds and bedding, particularly mattresses, is 
important in any attempt to free a house of the bugs. The use of iron 
bedsteads and bedding which is easily examined and treated facilitates 
control. 

Travelers frequently have their luggage infested while at hotels and 
in trains. On arrival at home it would be well to carefully examine the 
clothing before putting it away. 

Very frequently bedbugs are introduced into homes with laundry work 
which is carried to the home of the washwoman. Such wash work should 
be carefully inspected on receipt. 

LIST OF REFERENCES 

Blacklock, B., 1914.— Brit. Med. Journ., April 25, pp. 912-913. 
Brumpt, E., 1912.— Bull. Soc. Path. Exot., vol. 5, No. 6, pp. 360-367. 



402 SANITARY ENTOMOLOGY 

Brumpt, E., 1913a.— Bull. Soc. Path. Exot., vol. 6, pp. 167-169. 
Brumpt, E., 1913b.— Bull. Soc. Path. Exot., vol. 6, p. 170. 
Brumpt, E., 1913c— Bull. Soc. Path. Exot., vol. 6, pp. 382-383. 
Carmichael, 1899. — Med. News, Jan. 21. 
Carter, R. M., 1911.— Trop. Med. and Parasit., ser. T. M., vol. 5, 

pp. 15-32. 
Chagas, C, 1909.— Arch. Schiffs. u. Tropenhyg., Sept. 4. 
Cornwall, J. W., and La Frenais, H. M., 1915. — Ind. Journ. Med. Res., 

vol. 3, pp. 698-724. 
Cornwall, J. W., and Menon, T. K., 1917. — Ind. Journ. Med. Res., vol. 5, 

pp. 137-159. 
Cornwall, J. W., and Menon, T. K., 1918. — Ind. Journ. Med. Res., vol. 5, 

pp. 541-547. 
Fuller, C, 1919. — Report on Typhus Conditions in Native Dwellings. 

Union of South Africa. Dept. Agric, local series bull. 57. 
Howard, C. W., and Clark, P. F., 1912.— Journ. Exper. Med., vol. 16, 

No. 6, pp. 850-859. 
Knowles, R., 1918.— Ind. Journ. Med. Res., vol. 5, pp. 548-566. 
Long, E. C, 1911a. — Journ. Trop. Med. and Hyg., vol. 14, p. 17. 
Long, E. C, 1911b,— Brit. Med. Journ., Sept. 2. 
Manning, J. V., 1912a. — Med. Times, vol. 60, April. 
Manning, J. V., 1912b.— Med. Rec, vol. 82, No. 4, pp. 148-150. 
Marlatt, C. L., 1916.— U. S. Dept. Agr., Farmers' Bull. 754. 
Patton, W. S., 1907.— Scient. Mem. Officers' Med. & Sanit. Depts., Govt. 

India, n. s., Nos. 27, 31. 
Patton, W. S., 1912.— Scient. Mem. Officers' Med. & Sanit. Depts., 

Govt. India, n. s., No. 50. 
Patton, W. S., and Cragg, F. W., 1913.— A Text Book of Medical En- 
tomology, pp. 486-526. 
Pringault, E., 1914.— C. R. Soc. Biol., Paris, vol. 76, No. 19, pp. 881- 

884. 
Riggs, R. E., 1912.— Military Surgeon, vol. 31, pp. 279-288. 
Sangiorgi, G., 1910. — Centralb. f. Bakt. Paras, und Infekt., vol. 57, 

pp. 81-84. 
Skelton, D. S., and Parham, J. G., 1915. — Journ. Roy. Army Med. 

Corps, vol. 20, No. 3, pp. 291-292. 
Smith, A. J., Lynch, K. M., and Rivas, D., 1913. — Amer. Journ. Med. 

Sci., vol. 146, No. 5, pp. 671-681. 
Thompson, David, 1913.— Brit. Med. Journ., Oct. 4, pp. 847-849. 
Thompson, David, 1914. — Am. Trop. Med. and Parasit., vol. 8, No. 1, 

pp. 19-28. 
Wenyon, C. M., 1911.— Kala Azar Bull., vol. 1, No. 1. 



CHAPTER XXIX 

Diseases Caused or Carried by Mites and Ticks * 
W. Dwight Pierce 

The Arachnid order Acarina, composed of mites and ticks, contains 
many of the most serious carriers of causative agents of disease. As 
all ticks are parasitic on animals and derive their entire nourishment from 
the blood of their hosts, it is naturally to be expected that in this group 
we will find a great proportion of the carriers of animal blood diseases. 
The mites are not all parasitic, but there are quite a number of families 
in which parasitic mites are found, and some of the families are parasitic 
exclusively in their habits. 

The most familiar of all the tick-borne diseases is the disease known 
as TEXAS FEVER OF CATTLE which has cost the southern states 
millions of dollars, and has been the cause of restricting the shipment 
of cattle from southern to northern states. The discovery of the role of 
the tick in the transmission of Texas Fever by Smith and Kilborne of 
the Bureau of Animal Industry, was one of the earliest discoveries in 
medical entomology. Since that time the Department of Agriculture, 
through the investigations of the Bureaus of Animal Industry and 
Entomology has devoted a great deal of attention to this problem. The 
Bureau of Animal Industry has had charge of the eradication of the 
cattle tick in America and has succeeded in eliminating this pest from 
large areas and from at least one state, the State of Mississippi. 

In South Africa tick-borne diseases are the principal limiting factors 
to animal industry. The RELAPSING FEVERS of man in Africa are 
carried almost exclusively by ticks. In our own country one of the most 
serious local diseases is ROCKY MOUNTAIN SPOTTED FEVER in 
the northern Rocky Mountains. The relationship of the ticks and mites 
to disease can best be shown by an arrangement of these diseases accord- 
ing to their causative organism. 

DISEASES CAUSED BY DIRECT ATTACK OF TICKS AND MITES 

ACARINE DERMATOSIS or ACARIASIS. A great many different 
species of mites are capable of causing various types of DERMATOSIS 

x This lecture was prepared for the present edition. 

403 



404 SANITARY ENTOMOLOGY 

in man and animals. The BICHO-COLORADO ITCH is caused by the 
mite Tetranychus molestissimus Weyenbergh, which thrusts its hypos- 
toma into the skin of man and animals in Argentine and Uruguay. In 
Europe a similar dermatosis is caused by the related species T. telarius 
Linnaeus, variety russeolus Koch. These two species belong to the family 
Tetranychidae. 

The disease known as "GONONE" in Celebes and New Guinea is 
caused by the Trombidian mites Microtrombidium wichmanni Oudemans 
and Schongastia vandersandei Oudemans. This attack occurs both on 
man and animals. In Europe and America attack by various allied 
species is very common. The ordinary name for the attack is RED 
BUGS or CHIGGERS. The principal species which have been described 
as causing this attack are Microtrombidium tlalsaliuate Lamaire in 
Mexico ; Trombidium holosericeum Linnaeus, T. inopinatum Oudemans, 
and T. autummalis Shaw in Europe ; T. batatas Linnaeus in the West 
Indies ; Leptus americanus Riley, and L. iritans Riley in North America ; 
and also Trombidium striaticeps H. & O., Metatrombidium poriceps H. 
& O., Microtrombidium pusillum Hermann, and Alio trombidium fuligino- 
sum Hermann. The attack of chiggers is very painful and also difficult 
to relieve. Dusting of flowers of sulphur in the clothes is a good pre- 
ventive. I have had fairly good success in taking a hot bath immediately 
after coming from the field and then rubbing in ammonia. 

The allied species Leptus akamushi Brumpt not only causes a 
dermatosis, but also a definite disease which will be treated in a later 
paragraph. This is a Japanese species. 

A troublesome acarine dermatosis, which frequently causes swelling 
which may be dangerous, is caused by Holothyrus coccinella Gervais in 
Mauritius, which normally attacks dogs and geese, but also attacks 
children. 

In the family Parasitidae quite a number of species are charged with 
causing dermatosis. Dermanyssus gallinae Redi and D. hirundinis Her- 
mann, common avian parasites may also cause dermatosis in man. D. 
gallinae sometimes causes papular eczematous dermatosis. Liponyssus 
bacoti Hirst, a rat parasite in Australia, Africa and South America, 
occasionally causes dermatosis of people working in stores and granaries. 

URTICARIASIS is caused by various species of the family Tar- 
sonemidae. The mite, Pediculoides ventricosus Newport, causes a disease 
known under a number of different names, as GRAIN ITCH or ERY- 
THEMA URTICARIA. This mite becomes globular and reproduces 
its young at a very rapid rate. It burrows under the skin and is very 
painful. Many workers in harvest fields are attacked by this mite, espe- 
cially in Europe. It occurs quite commonly in America. A similar der- 
matosis is caused by Tarsonemus uncinatus, T. intectus, and Crithoptes 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 405 

monunguiculosus Geber. These three species may all be synonyms of 
Pediculoides ventricosus. 

A disease known as VANILLISMUS is caused in Europe by mites of 
the family Tyroglyphidae, Aleurobius farinae DeGeer, which is found in 
corn, Tyroglyplius siro Linnaeus, and Histiogaster entomophagus 
Laboulbene. In this same family are found other mites which cause 
diseases, posing under special names such as COPRA ITCH, caused by 
Tyroglyplius longior castellanii Hirst, in Ceylon ; GROCER'S ITCH, 
caused by Glyciphagus prunorum Hermann, in Europe; COOLIE ITCH 
or GROUND ITCH, caused by Rhizoglyphus parasiticus Dalgetty, in 
India. 

The itch or scab mites belong to the family Sarcoptidae. SCABIES 
or SARCOPTIC ITCH is caused by a species of the genus Sarcoptes, of 
which various species are described for the different animal hosts as fol- 
lows : Sarcoptes scabiei hominis Raspail, causing scabies of man in 
Europe and America, with the variety crustosae Fiirstenberg causing 
NORWEGIAN ITCH of man; S. bovisoi cattle (Sarcoptic Scab is com- 
paratively common in cattle in the United States, frequently a serious 
disease among bulls and dairy cattle) ; S. canis Gerlach of the dog; 
S. ovis Megnin of the sheep ; S. equi Gerlach of the horse ; S. suis Gerlach 
of the pig ; S. auclieniae Railliet of the llama ; S. dromedarii Gervais of 
the camel and dromedary and frequently of man ; S. caprae of the goat 
and rarely of man ; S. leonis Canestrini of the lion and rarely man ; 
S. vulpis Fiirstenberg of the fox. A similar itch is caused by Notoedres 
cati cati Hering and other varieties which attack felines, rodents, horses, 
and man. The sarcoptic mites live in burrows in the epidermis. Oint- 
ments containing sulphur are the best for these mites. 

PSOROPTIC ITCH or MANGE is caused by a species of the genus 
Psoroptes, of which Psoroptes communis ovis Hering causes SHEEP 
SCAB; variety bovis causes TEXAS ITCH of cattle; variety equi causes 
mange of horses and dogs. The psoroptic mites have piercing mandibles 
but do not burrow, although they may be greatly protected by scab 
formation over them. Among the dips used for the control of this itch 
are an 8 per cent kerosene emulsion used by Gillette ; and the Rutherford 
dip prepared by steeping 1 pound tobacco and adding thereto 1 pound of 
sulphur and 4 gallons of water, to be applied at 6 or 8-day intervals. 

CHORIOPTIC ITCH in the horse is caused by Chorioptes equi Ger- 
lach (symbiotes Verheyen) which attacks the hocks of the horse and 
causes the hair to fall out and sores to form. It also causes an itch 
of cattle, goats, and sheep. This species has piercing mandibles but 
does not burrow. According to Banks a mixture of 1 part carbolic 
acid to 15 or 20 parts of oil will destroy the mite. 

SCALY LEG of chickens is caused by Cnemidocoptes mutans Robin. 



406 



SANITARY ENTOMOLOGY 






ItiBfl tOr^KM Be ' ^B^bH r^Pa^^^^t ■*' 




WW* '- >ajT •? ,' Ip^E^ 1 " Ate 




W ^m m: m 'Jb J *'~'\4M 


1 JHL .^ft^vL „ 4 JEimt*3Kt 


w> i VJWL- .i,««Br 


- jV 




v^BBWBfe* -<il 


is 






.•* 


«»*** ^>ifajf ^^y^2 ft 






; 


4 



Plate XXIV. — Scaly leg mite on chickens. 

Fig. 1 (Upper). — Scaly feet of chicken, caused by mite attack. Fig. 2 (Lower) — Scaly 
leg mites, greatly enlarged. (Bishopp.) 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 407 

The mites form a crust of dead skin on the legs of the chickens (plate 
XXIV). The related species, Cnemidocoptes gallinae Railliet, causes the 
hens to pluck their feathers. The mites work at the base of the feathers 




Plate XXV. — Dipping scaly legs of chicken in crude oil (Bishopp.) 



and are called depluming mites. These mites are controlled by dipping 
in crude petroleum (plate XXV). 

DEMODECTIC MANGE, when caused by Demodex fotticulorwm 
Simon, gives rise to BLEPHARITIS, SEBORRHEA or BLACK- 
HEADS. Many animals and man are attacked by this mite. Probably 
a majority of persons harbor this mite. Demodectic mange is a common 
and practically incurable disease in dogs. Demodex phylloides Csoker 



408 SANITARY ENTOMOLOGY 

causes white tubercles on the skin of swine in the United States and 
Canada ; Demodex bovis Stiles causes swellings in the hide of cattle in 
the United States and other countries, damaging the hide. 

GUANO ITCH of man and dogs is caused by Tydeus molestus Moniez 
in Peru and Belgium ; it is found in guano. 

SEBACEOUS TUMORS in birds are caused by species Harpyryn- 
chus. H. longipilus Banks attacks the crossbill. Mice are attacked by 
the mites Psorergates simplex musculinus Mich, which lives in cavities 
beneath the surface of the skin, and Myobia musculi Schrank which de- 
velops in the hair follicles. 

ACARIASIS OF THE SENSE ORGANS. OTOACARIASIS is 
caused in man by Cheyletus eruditus Schrank and Acaropsis mericourti 
Laboulbene which attack the external auditory meatus. Rhizoglyphus 
parasiticus has also been recorded as causing Otoacariasis. Psoroptes 
cuniculi Megnin causes a rabbit ear mange which may result in death. 
Otodectes cynotis causes an otoacariasis of the dog and cat, which tor- 
ments the animals, resulting in convulsions and fits. Demodex folliculorum 
Simon is also credited with causing otoacariasis. 

Some of the ticks are also responsible for attacks of otoacariasis, as 
for instance the spinose ear tick Ornithodoros megnini (Duges) Neu- 
mann, which very commonly attacks the ears of cattle and horses and 
sometimes man in the southwestern United States. 

A fatal otoacariasis in the cow is charged to Dermanyssus gallinae 
Redi, but there is reason to question this. 

OCULAR ACARIASIS of the cornea may also be caused by Der- 
manyssus gallinae. 

INTERNAL ACARIASIS. CATARRHAL INFLAMMATION 
which may produce ASPHYXIA in chickens may be caused by Sternos- 
tomum rhinolethrum Trouessart and by a Rhinonyssus in birds. BRON- 
CHIAL INFLAMMATION which may produce asphyxia may be caused 
by Halarachne americani, H. attenuata, and H. halichaeri, all of which 
attack seals. INFLAMMATION OF THE LUNGS, which may pro- 
duce asphyxia, may be caused by Pneumonyssus simicola of the monkey. 
Cytoleichus nudus Vizioli occurs in the air passages of chickens and tur- 
keys, penetrating the tissues, and may produce asphyxia. C. sarcoptoides 
Heguin also attacks the air sacs in fowls. 

Nephrophages sanguinarius Miyake and Scriba is a doubtful parasite 
passed in bloody urine. Carpoglyphus alienus Banks has been found in 
purulent urine. A case of a cyst in the testis containing Histiogaster 
spermaticus Trouessart is recorded from India. Cytoleichus sarcoptoides 
Heguin is sometimes found in the liver and kidneys of the fowl. C. nudus 
Vizioli is suspected of producing PERITONITIS and ENTERITIS in 
chickens and turkeys. C. banksi Wellman also produces an internal 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 409 

acariasis in the squirrel. Laminosioptes cysticola produces a calcareous 
cyst in the subcutaneous tissues of chickens. 

GENERAL EFFECTS OF TICK BITE. The mites in attacking 
a host usually attack in numbers, or if individually, will be found to 
burrow into the skin, but the ticks merely attach themselves to the skin 
and draw blood. Tick bites are very likely to cause a PRURITIS which 
in some cases will be painful for months or sometimes years. This is 
especially true in the case of Argas reflexus (Fabricius) Latreille which 
causes a painful bite marked for years by a cicatrix at the site of the 
attack. Argas brumpti Neumann causes a pruritis the site of which 
remains indurated for years. The bite of Ornithodoros coriaceus Koch 
is very painful; the bites are slow healing. The bite of Ornithodoros 
turicata (Duges) Neumann may cause dermatitis and lymphangitis. The 
bite of Ixodes ricinus (Linnaeus) Latreille may cause in man abscesses, 
edema, lymphangitis, and fever; it may penetrate beneath the skin and 
produce a tumor. The bite of Ixodes (Ceratixodes) putus (Picard- 
Cambridge) Neumann is painful to man. It normally attacks birds. 
The bite of the "conchuda," Ixodes bicornis Neumann, is sometimes fatal 
to infants. 

TICK PARALYSIS. The bite of certain ticks causes paralysis of 
man and animals. The NORTH AMERICAN HUMAN TICK 
PARALYSIS is caused by the same tick which causes Rocky Mountain 
Spotted Fever, Dermacentor andersoni Stiles {venustus Banks) 2 in the 
northwestern States, and British Columbia, but a case is recorded from 
California caused by Ornithodoros coriaceus Koch. Todd has described 
a typical case of paralysis in children as follows: an active and appar- 
ently healthy child suddenly develops a paresis or paralysis of the legs ; 
neither abnormal temperature nor any other symptoms of paralysis is 
constant. . After the discovery of the tick and its removal the symptoms 
disappear in a few hours with a possible exception of a more or less 
local reaction, often probably due to a secondary bacterial infection at 

2 In view of the contention of Mr. Bishopp that venustus is the name of the fever 
tick it is necessary to give my reasons for the adoption of andersoni. 

Dermacentor venustus Marx in Neumann (1897) is cited as an undescribed synonym 
of D. reticulatus Fabricius. 

In 1905 Stiles named the Rocky Mountain Spotted Fever tick as D. andersoni, 
strengthening his description in 1908 and 1910. 

In 1908 Banks drew up the description, as a new species, of Dermacentor venustus 
(Marx) from the Marx material, which was subsequently examined by Stiles and 
found to consist of three lots of material of at least two species. Stiles definitely 
picked from Banks' type material Marx No. 122 as type of species D. venustus. Since 
both Marx and Banks confused more than one species and neither designated a type 
fiom the material, Stiles' type designation is valid. 

In 1910 Stiles differentiates between the two species andersoni and venustus. 

Even if he should be found to be wrong in considering these as two species, 
andersoni antedates venustus. But in order to set this question at rest an appeal has 
been made to the International Commission of Zoological Nomenclature for a ruling 
on the name of this tick. (W. D. Pierce.) 



410 SANITARY ENTOMOLOGY 

the site of the tick's bite. In some cases which have been reported the 
tick was not removed and in these the paralysis progressively involved 
the whole body until reflexes and control of the sphincters were lost and 
death ensued. Abscesses following a tick bite are probably due to the 
head of the tick remaining in the wound. The symptoms suggest infan- 
tile paralysis but they may be distinguished from cases of that disease 
by the invariably transitory nature of the paralysis. The tick paralysis 
never leaves permanent disability. Various doctors practicing in the 
Northwest have described cases, some of which have been fatal. In case 
of paralysis it is always well to make a thorough search of the body, espe- 
cially in the vicinity of the spinal column, for the ticks. They are quite 
commonly found in the hair at the base of the head. The exact cause 
of the paralysis is unknown, but it is believed that it is caused either by 
the injection of a specific poison into the body by the tick, or by the 
reactions which take place, forming poisons during the presence of the 
tick's head in the body. The only treatment necessary is the removal of 
the tick by excision in order to make sure that the mouth parts are 
removed, and the dressing of the wound antiseptically. Purgatives and 
stimulants should be given. Dermacentor andersoni also causes a paraly- 
sis of animals similar to that in man ; in the case of sheep the effect on the 
body is a loss of balance, causing the sheep to fall in places from which 
they cannot extricate themselves. If the tick is removed in time the 
animal will recover. 

South African TICK PARALYSIS in animals is caused by the bite 
of Ixodes pilosus Koch which attacks sheep principally. The effect of 
this paralysis is to cause the sheep to become very unsteady on their 
feet and to lie down frequently. They seem to recover rather rapidly, 
death being usually caused by their becoming prostrated in the open where 
they fall victims of jackals. There are no fever reactions. Dipping 
with Cooper's Dip is considered a very effective control measure. 

HUMAN TICK BITE FEVER of Lourenco Marques is caused 
principally by the larva of Amblyomma hebraeum Koch but occasionally 
by Rhipicephalus simus Koch and Boophilus annulatus (Say) Stiles and 
Hassell 3 and B. annulatus (decoloratus Koch). The patient at first 
complains of general weakness, muscular pains and especially of con- 
siderable difficulty in moving his arms and legs. The glands in the neck 
become swollen in a short time, those situated in the nape of the neck 

3 Mr. Bishopp writes that he prefers Margaropus to Boophilus for this tick and its 
allies. My reasons for adopting Margaropus are as follows: 

1. Margaropus Karsch and Boophilus Curtice are considered by Nuttall, War- 
burton, Cooper, and Robinson (1911) to be two distinct genera. The type of the 
former is designated by them as Margaropus winthemi Karsch, and of the latter 
Boophilus annulatus (Say) Curtice. 

2. Boophilus annulatus is a name well established in medical literature. (W. D. 
Pierce.) 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 411 

being chiefly involved. The patient suffers from severe occipital headache 
with considerable rigidity of the muscles of the nape of the neck, so that 
the head may be turned to one side as in torticollis. The superficial 
glands in the groin and axilla are found to be enlarged and acutely pain- 
ful. The acute neck symptoms begin to subside from the eighth to tenth 
day and recovery takes place spontaneously, but the glandular enlarge- 
ment persists a month or more after recovery. The glands become hard 
and painless. 

AUSTRALIAN HUMAN TICK PARALYSIS is caused by either 
Ixodes ricinus (Linnaeus) Xatreille or Ixodes holocyclus Neumann and 
is very similar to the American tick paralysis. Eaton considers that there 
are three possibilities as the cause of the paralysis : pre-f ormation of the 
poison by the tick, development of the infective organism in the blood, or 
liberation mechanically or biologically (by bacterial introduction) at the 
site of the bite, of some poison subsequently absorbed. 



DISEASES CARRIED BY MITES AND TICKS 

Ticks and mites are the carriers of many diseases. 

DISEASES CAUSED BY PLANT ORGANISMS 

There are undoubtedly many cases of SEPTICEMIA due to the intro- 
duction of plant organisms at the site of the bite of the tick. These are 
most likely to be streptococcal and staphylococcal infections. For in- 
stance, the bite of Argas reflexus (Fabricius) Latreille has been known 
to give rise to FURUNCULOSIS caused by Staphylococcus pyogenes 
(Nuttall, Warburton, Cooper, and Robinson, 1908). Ixodes ricinus 
(Linnaeus) Latreille may also carry infections of Staphylococcus 
pyogenes (Nuttall, Warburton, Cooper, and Robinson, 1911). 

Demodex folliculorum Simon, the blackhead mite, causes an irritation 
giving rise to papules which become infected with Bacillus necrophorus. 

Jarvis has just published an article in which he claims that EPIZOO- 
TIC LYMPHANGITIS is an inoculable disease through the agency of 
the ticks of the genus Amblyomma. The disease is characterized b}' sup- 
puration, ulceration, and necrosis. He believes that the lesions are caused 
by a variety of micro-organisms including the Priesz-Nocard organism, 
the Cryptococcus farciminosus, the Bacillus necrophagus, and Staphylo- 
cocci, and that these organisms are introduced through the agency of the 
mouth parts of the ticks which are very long and pierce the whole integu- 
ment, reaching the subcutaneous layers where the bacteria can easily set 
up lesions. 

Hadwen has just published an article in which he shows that ticks play 



412 SANITARY ENTOMOLOGY 

an important role in producing FISTULOUS WITHERS. He con- 
siders Dermacentor albipictus Packard as the worst offender, but also 
considers D. andersoni Stiles (venustus Banks) as a cause. D. albipictus 
is commonly called a winter tick and in some regions of British Columbia 
where poll evil and fistulous withers are common, horses are heavily 
infested with these ticks. The favorite site of attachment is along the 
whole length of the mane from the poll to the withers. At the point of 
attachment there is often a necrotic spot if the tick has been attached for 
a few days. It is easy to see that these necrotic spots should be a 
favorite point of entrance for bacteria. 

It is quite probable that most of the cases of abscesses and irritation 
resulting from tick bites are due to secondary infections by bacteria 
which may possibly be mechanically introduced by the tick itself. No 
one has given this question serious attention. 



DISEASES OF UNKNOWN ORIGIN 

There are quite a number of instances of so-called tick fever caused by 
the bite of ticks, of which the exact cause is unknown. Among these are 
unnamed TICK FEVERS caused by Ornithodoros savignyi Audouin 
(Koch) and Hyalomma aegyptium (Linnaeus) Koch. 

HEART WATER, a disease of sheep, caused by a filterable virus, is 
transmitted by Amblyomma hebraeum Koch. 

The TICK FEVER OF MIANA is caused by the bite of Argas 
persicus Oken. 

INTERMITTENT FEVER of Wyoming, which is possibly identical 
with Rocky Mountain Spotted Fever, is thought by Castellani and Chal- 
mers to be caused by Dermacentor andersoni Stiles (venustus Banks). 

ROCKY MOUNTAIN SPOTTED FEVER, a disease characteristic 
of the Rocky Mountains of Montana and Idaho and occasionally other 
nearby states, was proven by Ricketts to be transmitted by the tick 
Dermacentor andersoni Stiles (venustus Banks), by D. variabilis (Say) 
Banks and possibly by D. modestus Banks. 

The first scientific article in which the tick is mentioned as a possible 
carrier of this disease was published by Wilson and Chowning in 1902. 
They subsequently published the reports of their investigations but they 
did not prove that the tick was actually the transmitting agent. An- 
derson (1905) was so convinced that the tick was the cause of the fever 
that he published an article calling it the SPOTTED FEVER or TICK 
FEVER of the Rocky Mountains. Stiles in 1905 did not attribute the 
disease to ticks. Finally Ricketts in 1906 began a thorough investiga- 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 413 

tion of the cause of the disease and proved transmission of the disease 
to a guinea pig by Dermacentor andersoni Stiles (occidentalis Stiles, not 
Marx). This preliminary report by Ricketts was followed by numerous 
other papers by himself on the subject, until he had definitely proven the 
relationship of the tick to the disease. The organism causing spotted 
fever has just been described. Wilson and Chowning described Piroplasma 
hominis as the causative organism, but their work has not been corrob- 
orated by others. Very recently Wolbach (1919) has found bodies some- 
what similar to the Rickettsia bodies found in typhus fever and trench 
fever. He describes his organism as Dermacentroxenus rickettsi Wol- 
bach, but is uncertain as to its location in classification. It is intra- 
cellular in mammal and tick, and intranuclear in ticks. Two multiplica- 
tive forms and an infective form are found in the tick, and only the latter 
is regularly found in mammals. Wolbach's volume is the latest and most 
complete treatise on all phases of the disease and is well illustrated. 

Mayer (1911) conducted transmission experiments and was success- 
ful in transmitting the disease by Dermacentor marginatus Banks, 
Amblyomma americanum (Linnaeus) Koch and Dermacentor variabilis 
(Say) Banks. 

The role of wild animals in acting as reservoirs for the disease has not 
been definitely determined although several wild mammals have been shown 
to be susceptible. It is probable that it is by this means that the disease 
is perpetuated. The ticks which carry the disease are normally found 
on wild animals in the immature stages and the adults usually engorge 
on the larger domestic animals and to some extent on the larger wild 
mammals. The Rocky Mountain Spotted Fever is transmitted heredi- 
tarily by the tick. Control of the disease must be effected by destruction 
of the adult ticks on domestic animals, reduction of the numbers of wild 
hosts, and prevention of tick attack on man. 

TSUTSUGAMUSHI DISEASE, sometimes called JAPANESE 
RIVER FEVER or KEDANI DISEASE, has been proven to be carried 
by the mite Leptus akamushi Brumpt (Trombidium). Kitashima and 
Miyajima have proven that this disease is not caused by the bite of all 
mites of this species, but only by certain ones, and consider that the evi- 
dence is sufficiently strong to assume that the disease is caused by a non- 
filterable virus which can be inoculated by the mites only after they have 
become infected. They conducted a large number of experiments to prove 
the role of the mite. The field mouse, Microtus montebelli, is susceptible 
and is believed to be the important natural host of the virus. (It is inter- 
esting to note that another Japanese disease, Seven Day Fever, caused by 
Leptospira hebdomadis Ido, Ito and Wani has the same mouse, Microtus 
montebelli as its reservoir.) 



414 SANITARY ENTOMOLOGY 

DISEASES OF ANIMAL ORIGIN 

Protozoa 
Mastigophora: Binucleata: Trypanosomidae 

Schizotrypanum cruzi Chagas, the cause of CHAGAS FEVER, while 
normally transmitted by the kissing bugs of the genus Triatoma, has been 
shown by Brumpt to develop in the tick Ornithodoros moubata (Murray) 
Pocock, and by Neiva (1913) to develop in Rhipicephalus sanguineus 
(Latreille) Koch. 

Trypanosoma sp. which is supposed to cause a reptilian disease, is 
carried by Amblyomma testudinis (Conil) Neumann. 

Trypanosoma Christopher si Novy is an organism probably native 
to Rhipicephalus sanguineus (Latreille) Koch and was originally recov- 
ered from ticks fed on dog. 

Mastigophora: Binucleata: Leptomonidae 

Some authors are inclined to separate the genera of tick organisms 
to form the family Piroplasmidae. These organisms do seem to form a 
rather consistent family which contains the genera Theileria, Nuttallia, 
Babesia, Piroplasma, Rossiella, and Anaplasma. 

Anaplasma argentinum, the cause of ARGENTINE ANAPLASMO- 
SIS of cattle, is carried by Boophilus annulatus australis Fuller {micro-, 
plus Canestrini) {Lignieres 1914). 

Anaplasma marginale Theiler, cause of ANAPLASMOSIS of many 
African and Australian animals, is transmitted according to Theiler 
(1910) by Boophilus annulatus (decoloratus Koch), and according to 
Castellani and Chalmers by Rhipicephalus simus Koch. 

Babesia argentinum, cause of Argentine BABESIASIS OF CATTLE, 
is carried by Boophilus annulatus australis Fuller (microplus Canestrini) 
(Lignieres 1914). 

Babesia bovis Babes (Piroplasma bigeminum Smith and Kilborne), 4 
the cause of TEXAS CATTLE FEVER which is also known as RED 
WATER, SPLENIC FEVER, SOUTHERN CATTLE FEVER and 
under various other names, is normally transmitted by the cattle tick 
Boophilus annulatus (Say) Stiles and Hassall in North America. The 
first proofs of tick transmission were published by Smith and Kilborne 
(1893). Crawley (1915) believes the organism is pathogenic to this 
tick. The organism may also be transmitted by Boophilus annulatus 
australis Fuller (decoloratus Koch) in South America, Cuba, Porto Rico, 

4 Babesia bovis and B. bigeminmn are separated by some authors as two distinct 
species, bovis causing the European disease, and bigeminum the American. 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 415 

Philippines, and Australia, according to various authors, and by Boo- 
philus annulatus australis (microplus) in South America (Lignieres), 
and B. annulatus decoloratus and Rhipicephalus capensis Koch in Africa. 
Carpano (1915) suspects Hyalomma aegyptium (Linnaeus) Koch to be 
the carrier of Babesia annulatum, a synonym of bovis which is recorded 
as the causative organism of MEDITERRANEAN COAST FEVER OF 
CATTLE. 

The first contributions to the life history of this organism were made 
by Smith and Kilborne. It is found in the blood of the animal hosts in 
the first stage, being inside the red blood cells near its margin, and is 
non-motile and pale. This single body develops incompletely into two 
small roundish bodies which are partially connected by a narrow inter- 
vening strand. In the next stage the minute, double, rounded bodies 
become enlarged and spindle-shaped. They probably remain attached, 
however. The two bodies enlarge uniformly and assume a pear-shaped 
appearance. At this stage of the life cycle, the disease is in its most 
acute form. The parasites occupy nearly one-fourth of the body of the 
red blood cells and from 0.5 to £ per cent of the red cells are usually 
invaded. The blood cells finally break up, liberating the parasites which 
may be observed as free bodies in the circulation. The parasites are 
taken up by the tick, according to Koch, in the red blood cells. In the 
body of the tick the parasites leave the red cell and become long and 
club-shaped. From the club pseudopodia project. This club then be- 
comes spherical and immense numbers of amoeba-like forms appear, which 
are said to grow into clubs. The disease can only be transmitted by 
seed ticks, that is, by the first stage of the tick. The adult tick which 
sucked up the infected blood drops to the ground and lays its eggs. The 
organism passes into the eggs and is transmitted to other animals by the 
offspring of the tick which became infected. The disease can be given 
to a host almost immediately after attachment. The tick remains on 
the animal throughout its development (Mohler 1905). 

Babesia caballi (Nuttall), the cause of EQUINE BILIARY FEVER, 
is considered by Marzinowski and Bielitzer (1909) to be carried by Der- 
macentor reticulatus (Fabricius) Koch in Russia. According to Valla- 
dares (1914), there is a possibility that Hyalomma aegyptium (Lin- 
naeus) Koch is the carrier in India. 

Babesia canis (Piana and Galli-Valerio) the cause of a CANINE 
BABESIASIS, also known as MALIGNANT JAUNDICE OF DOGS, is 
transmitted by several ticks. The life cycle has been traced in Rhipiceph- 
alus sanguineus (Latreille) Koch by Christophers in India (fig. 78). 
Lounsbury proved the transmission of the disease in South Africa by 
Haemaphysalis leachi (Audouin) Neumann. According to various au- 
thors Dermacentor reticulatus (Fabricius) Koch carried the disease in 



416 



SANITARY ENTOMOLOGY 



France. Ixodes heocagonus Leach (reduvius Audouin), and /. ricinus 
(Linnaeus) Latreille, are suspected to be carriers. The life cycle in the 
dog was worked out by Nuttall and Graham-Smith (1904-7). The cycle 
of schizogony is passed in the dog. The free pyriform parasite enters 
a normal red blood corpuscle and becomes rounded in shape. The parasite 
throws out pseudopodia and appears as an amoeba. This stage lasts a 
long time, at the end of which the parasite enters upon a quiescent stage. 
Finally the organism takes a form called the trefoil stage, in which the 
main mass of the chromatin, much reduced in size, lies at the base of 
the two processes. Two nuclei are formed, finally the cytoplasm divides 




and two pyriform parasites are found lying side by side in one corpuscle. 
The corpuscle now ruptures and liberates the two parasites. 

Christophers has worked out the cycle of sporogony in the tick. When 
an adult or nymphal tick bites a dog and takes in blood containing the 
oval parasites, these develop in the gut into round or oval bodies which 
finally assume the form of a club-shaped bod}' which gradually becomes 
ookinete. In the adult these ookinetes wander into the ova, while in the 
nymph they simply pass into the embryonic tissues. In either case they 
become rounded and form a zygote which breaks up into sporoblasts, 
and these again into sporozoites which infect the salivary glands of the' 
nymph and the adult of the second generation. 

A parent tick having gorged with blood falls to the ground and 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 417 

lays her eggs which develop into six-legged larvae. They do not infect 
the dog, which they attack as soon as possible and on which they remain 
two days sucking blood. After dropping off they in due time shed their 
larval skin and become eight-legged nymphs which again attack the dog, 
but do not infect it. The nymph, after dropping off, undergoes meta- 
morphosis and sheds its nymphal skin, and becomes the sexually mature 
tick, which is the only form that spreads the infection, according to 
Lounsbury (1901), and Nuttall. 

Babesia diver gens (McFadyean and Stockman), the cause of British 
RED WATER OF CATTLE, is principally carried by Ixodes ricimus 
(Linnaeus) Latreille, although McFadyean and Stockman succeeded in 
transmitting the disease by means of Haemaphysalis cinnabarvna 
punctata Canestrini and Fanzago (Nuttall, Warburton, Cooper, and 
Robinson, 1915). 

Babesia gibsoni (Patton), cause of BABESIASIS OF THE JACKAL 
AND DOG, is said by Neumann to be carried by Rhipicephalus simus 
Koch. Patton found infested jackals with Haemaphysalis birmaniae 
Supino (bispinosa) and Rhipicephalus simus Koch but did not prove 
that they were infected. 

Babesia minense Yakimoff, the cause of BABESIASIS OF THE 
HEDGEHOG, is said by Doflein to be carried by Dermacentor reticula- 
tus (Fabricius) Koch. 

Babesia ovis (Babes), the cause of CARCEAG of sheep, is heredi- 
tarily transmitted by Rhipicephalus bursa Canestrini and Fanzago.. The 
daughter adult tick, developed from a tick which sucked the blood, is 
the stage which transmits the disease. The disease has been trans- 
mitted by Haemaphysalis cinnabarina punctata Canestrini and Fanzago 
experimentally. 

Crithidia haemaphysalidis Patton is hereditary in Haemaphysalis 
birmaniae Supino (bispinosa) in India. 

Crithidia hyalommae O'Farrel is hereditary in Hyalomma aegyptium 
(Linnaeus) Koch in the Sudan. 

Nuttallia equi (Laveran), the cause of NUTTALLIOSIS OF 
EQUINES, was demonstrated by Theiler to be transmitted in South 
Africa by Rhipicephalus evertsi Neumann. Considerable evidence points 
towards Hyalomma aegyptium (Valladares 1915). 

Rossiella rossi (Nuttall), the cause of JACKAL ANEMIA, is thought 
by Nuttall to be possibly carried by Haemaphysalis leachi (Audouin) 
Neumann. 

Theileria parva (Theiler), the cause of EAST COAST FEVER or 
RHODESIAN FEVER, has been known by Theiler (1903, 1904, 1908) 
and Lounsbury (1906) to be transmitted by Rhipicephalus appcndicu- 
latus Neumann, R. simus Koch, R. evertsi Neumann, R. capensis Koch 



418 SANITARY ENTOMOLOGY 

and Dermacentor nitens Neumann. It is also recorded from Hyalomma 
aegyptium (Linnaeus) Koch by Carpano (1915) and Dermacentor reti- 
culatus (Fabricius) Koch (Doflein 1911). The ticks do not produce an 
infection during the first two days after they have taken up the infective 
organism. They may transmit the organism in the instar following that 
in which they ingested the blood containing the organisms. 

Mastigophora: Spiroc'hcetacea: Spiro chat idee 

Spiroschaudinnia sp. (duttoni Brumpt, not Novy and Knapp), the 
cause of ABYSSINIAN RELAPSING FEVER, was transmitted by 
Brumpt to monkeys, rats, and mice by means of Ornithodoros savignyi 
(Audouin) Koch. 

Spiroschaudinnia anserina (Saccharoff), the cause of GOOSE 
SPIROCHAETOSIS, Transcaucasia, is carried by Argas persicus 
(Oken) Fischer Von Waldheim (Saccharoff 1891). 

Spiroschaudinnia duttoni (Novy and Knapp), the cause of RE- 
LAPSING FEVER of tropical and west Africa, is hereditarily trans- 
mitted by Ornithodoros moubata (Murray) Pocock. The transmission 
by this tick was first proven by Dutton and Todd in 1905. Many others 
have corroborated this. Mollers in 1907 showed that infected ticks, fed 
successively on six clean animals, after each feed may lay a batch of 
infected eggs. The ticks hatched from these eggs are capable of con- 
veying the infection to the animals they feed upon. Moreover, not only 
is the infection carried through the second generation, but also through 
their offspring, ticks of the third generation being found to be infective 
even though their parents have never fed on an infected animal. Schuberg 
and Manteufel (1910) and Hindle (1911) found that about 30 per cent 
of the ticks are immune to spirochaetal infection. In man the parasite 
is ribbon-shaped on transverse section and though it is in spirals, may 
be simply waved. A narrow undulating membrane is sometimes present. 
Reproduction is by longitudinal as well as transverse fission and also by 
granular formation. The latter method occurs just before the crisis, 
when the blood is swarming with parasites. They are then to be seen 
coiling themselves up in the spleen, bone marrow, and liver, and becoming 
surrounded by a thin cyst wall. In this cyst the parasite becomes more 
and more indistinct and breaks up into filterable granules. 

Leishman found that when the organism finds its way into the intes- 
tinal sac of the tick it loses its mobility and characteristic appearance, 
and chromatic masses escape into the lumen of the gut in the form of 
small rods or rounded bodies. These multiply and pass into the cells of 
the Malpighian tubules. Hindle found the spirochaetes always present 
in the gut of infected ticks, often in the Malpighian tubules and sexual 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 419 

organs, very seldom in the salivary glands, and not at all in the coxal 
fluid. Leishman in 1910 proved that the organism is voided in Mal- 
pighian excrement while the tick is feeding, and, by means of an anti- 
coagulin coxal fluid voided at the same time, is washed into the wound. 
Infection does not take place through the proboscis. Leishman's experi- 
ments were completely checked and substantiated by Hindle (1911), who 
demonstrated that the infection was due to the presence of the spiro- 
chaetes in the white Malpighian secretions, and entered the feeding punc- 
tures with uninfected coxal fluid; and, furthermore, dissections prove 
that the salivary glands of these particular ticks were not infected, while 
the gut contents, sexual organs and Malpighian tubules were. Inocula- 
tion of these various organs gave incubation of spirochaetes in 7 to 9 
days. 

Spiroschaudinnia granulosa (Balfour), cause of Sudanese or North 
African FOWL SPIROCHAETOSIS, was proven by Balfour to be 
transmissible by Argas persicus (Oken) Fischer Von Waldheim. 

Spiroschaudinnia marchouxi (Nuttall), the cause of Brazilian or 
South American F0WL SPIROCHAETOSIS, was shown by Marchoux 
and Salimbeni to be carried by Argas persicus. This has been corrob- 
orated by Nuttall, Hindle, and others. Shellack transmitted the disease 
by Argas reflexus (Fabricius) Latreille. In experiments conducted at 
Hamburg, Fiilleborn and Mayer transmitted the disease by Ornithodoros 
moubata. Nuttall working with the Brazilian strain, found that when 
the spirochaetes first enter the tick they soon disappear from the gut ; 
a certain number degenerate while others traverse the gut wall and enter 
the coelomic cavity to circulate all over the body. They enter various 
organs, especially the cells of the Malpighian tubules and sexual organs, 
in which the}' break up into a large number of small particles or coccoid 
bodies which multiply by fission and give rise to large agglomerations. 
These coccoid bodies may also be found in the lumen of the gut and Mal- 
pighian tubules and in the excreta. According to Nuttall, the tick in the 
act of feeding occasionally voids excrement and exudes a few drops 
of secretion from the coxal glands situated in the first intercoxal space, 
the fluid pouring out of a wide duct and being rapidly secreted from the 
freshly imbibed blood serum. This fluid, as well as the salivary and intes- 
tinal secretions of Argas, contains an anticoagulin. The coxal fluid dilutes 
the escaped excrement and facilitates its getting into the wound inflicted 
by the tick. This is doubtless the usual mode of infection, the coccoid 
bodies in the excrement gaining access to the body of the host and after- 
wards developing into spirochaetes, though the latter development lias 
not actually been followed. The bird begins to show symptoms after a 
period of incubation of about four da} T s following upon the bite of the 
infected tick. 



420 SANITARY ENTOMOLOGY 

Hindle has found the coccoid bodies within the Malpighian cells of 
the embryo tick. If the eggs are maintained at 37° C. the coccoid bodies 
grow out and assume a form which suggests that they are on the way 
to forming spirochaetes. This indicates hereditary infection. 

Spiroschaudinnia neveuocii (Brumpt), the cause of Senegal FOWL 
SPIROCHAETOSIS, is spread by Argas persicus, according to Brumpt. 

Spiroschaudinnia novyi (Shellack), the cause of American or Colom- 
bian RELAPSING FEVER, may be transmitted by Ornithodoros turicata 
(Duges) Neumann according to Brumpt, 0. megnini (Duges) Neumann 
according to Doflein, O. moubata (Murray) Pocock according to Nut- 
tall, and Argas persicus (Oken) Fischer Von Waldheim according to 
Doflein. 

Spiroschaudinnia recurrentis (Lebert), the cause of European 
RELAPSING FEVER, is normally transmitted by lice and bedbugs, but 
Manteufel found that the disease could be easily transmitted by Ornitho- 
doros moubata. 

Spiroschaudinnia rossii (Nuttall), the causing of East African 
RELAPSING FEVER, may be spread by Ornithodoros moubata, 
according to Nuttall. 

Spiroschaudinnia theileri (Laveran), the cause of BOVINE SPIRO- 
CHAETOSIS, was proven by Theiler to be transmitted by Boophilus 
annulatus decoloratus. It may also be transmitted by Rhipicephalus 
evertsi Neumann. The organism is hereditar}' in B. annulatus (decolo- 
ratus) as proven by Laveran and Vallee. The disease appears in 14 
days after inoculation by a larval tick (Nuttall 1913). 

Telosporidia: Haemogregarinida: Haemogregarinidae 

Haemogregarina (Hepatozoon) canis (James), the cause of CANINE 
ANEMIA, has been shown bj r Christophers to pass its cycle of sporogony 
in Rhipicephalus sanguineus (Latreille) Koch; the cycle of schizogony is 
passed in the dog (fig. 79). Schizogony appears to take place only in the 
bone marrow and does not take place in the liver or spleen. When a 
tick sucks the blood of the dog it takes up the encapsuled forms which 
pass into the stomach. The parasite escapes from the blood of the cor- 
puscles but is still inside its own envelope. By elongation and passage 
of the protoplasm behind the nucleus, the oval parasite becomes a vermi- 
cule. The vermicules enter young epithelial cells lining the lumen of the 
gut in whose cytoplasm they divide by fission, which often takes place 
several times, resulting in the secondary formation of four to eight ver- 
micules lying in a pocket in the cytoplasm of the cell. Two of these 
secondary vermicules, which apparently do not differ in appearance, 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 421 

conjugate and the nuclei fuse, and then follows a throwing out of two 
large masses of chromatin from the nucleus and the separation of a 
portion of cytoplasm resulting in the formation of an oocyst with a syn- 
karyon. The oocyst, still imbedded in the epithelial cell, grows rapidly, 
becoming irregular in form. Later stages of development are only 
found in ticks which ingest vermicules during their nymphal stage. The 
oocyst divides into four cysts which grow very large. These may rupture 
and release into the body cavity the sporocysts which contain the 
sporozoites. 

After sucking the blood of a dog from two to four days, the adult 



MPHORnDULTl 




cucA-rro 
Of Host I 
By An Adult 

T.ck 



~£PoRocr£| 

CVH-rl +***»*"' 

During Process 
Of Engorgement 



Cycle of Schizogony 
I n Canis familiaris (Dos) 



Cycle of Sporogony 
In Rhipicephalus sanguineus 
(DosT.ck). 



LIFE CYCLE OF HAEMOGREGARINA CANIS. 

TheCauseof Canine Anemia. 

(Constructed After Descriptions ano Drawiimqs by ChbistophersJ 

Fig. 79.— ( Pierce). 



tick drops off never to feed again. It is apparent then, that the adult 
tick taking up infected blood for the first time in this stage of its develop- 
ment, cannot of itself transmit the disease, as the parasite has been shown 
by Christophers not to complete its development in the adult. We must, 
therefore, look to the life history of the tick to find the possible method 
of transmission. Christophers found that complete development in the 
tick only occurs when the parasite is taken up in the nymphal stage. He 
did not find any parasite in larvae fed on infected dogs. After the nymphal 
stage the ticks drop off from the host for molting. They then reattach 
as adults and engorge. The possibility of infecting a new host is very 
great because of this change of host during the development of the 
parasite in the tick. 



422 SANITARY ENTOMOLOGY 

Haemogregarina (Haemogregarina) mauritanica (Sergent and Ser- 
gent), a parasite of Testudo mauritanica, is transmitted by Hyalomma 
aegyptium (Linnaeus) Koch, according to Von Prowazek. 

Haemogregarina (Hepatozoon) jaculi (Balfour), parasite of the 
jerboas (Jaculus gordoni and J. orientalis), while usually carried by 
the flea, may be carried by the mite, Dermanyssus gallinae Redi, according 
to Von Prowazek. 

Haemogregarina {Hepatozoon) leporis (Patton), a parasite of the 
rabbit Lepus nigricollis, may be mechanically carried by Haemaphysalis 
flava Neumann in India, according to Von Prowazek. 

Haemogregarina (Hepatozoon) muris (Balfour) the cause of RAT 
ANEMIA, was found by Miller to pass its schizogony in the rat and its 
sporogony in the rat mite Laelaps echidninus Berlese. In sucking the 
blood of the rat the mite takes up the leucocytes containing the gameto- 
cytes of this organism, which are then liberated from their cells by the 
digestive action of the mite's gut. They arrange themselves in couples 
which are at first quite similar, but which later differentiate into macro- 
gametes and microgametes. Zygosis now takes place forming an ookinete 
which grows, and, leaving the gut by piercing the wall, forces its wa} r 
into the body cavity and further into the sheaths of the muscles and 
into the investing membrane of the salivary glands. In the tissues it 
encysts and becomes the oocys'c which grows rapidly in size and under- 
goes nuclear division. The daughter nuclei migrate to the periphery 
which becomes covered with 50 to 100 bud-like projections, in each of 
which a nucleus is to be found. These buds break off from the central 
mass and form sporoblasts, the nuclei of which divide to form daughter 
nuclei which gather at the poles, while the whole sporoblast encysts. 
Short rod-like processes of cytoplasm, each containing a nucleus, now 
break off from the sporoblast and become sporozoites, of which there 
are on an average 16 to each sporoblast. 

Infection of the rat takes place by ingestion of the mites, when the 
sporozoites are liberated by the juices of the duodenum and become 
actively motile, striated vermicules which penetrate the intestinal villi, 
enter the blood system, and are carried to the liver, into the cells of 
which they penetrate and start the cycle of schizogony. As the mites 
leave the rats during the daytime, only feeding on them during the night, 
it is easy to understand the manner in which the disease spreads from 
the sick to the healthy. 

Haemogregarina (Karyolysus) lacertarum (Danilewsky), a parasite 
of lizards of the genus Lacerta, is recorded by Chatton and Roubaud from 
nymphs of mites of the family Dermanyssidae, in which the cycle of sporog- 
ony takes place. 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 423 



AouLTS Attack WosT'sT^to N; 
Mate And Drop Replete; 
Females Oviposit 
Each Time .-. 



Moults Emerge. From' 
SecomdN' 




MALE LIVES ON. « 
^Ovi position Commences. 



Larvae Hatch Out. 
FEMALE LIVES ON 



ARVAtMlTAex 



HostI 



Replete Larvae Drop 

From Host I 



■ First Nymph aL Stage 
Emer6EsFron> Larval Skim. 

First Nvmphal Stage Attacks.Host II 
And Drops Off Replete. 



SeconoNymphal Stage Attacks Host ID, 
And Drops Off Replete . 



TICKLIFECYCLE-TYPEI 

Life Cycle of Argas persjcus, also probably A reflexus. 

A.VESPERTILIONIS AND SOMEOTHER SPECIES OF ARGA.S AND OrNITHOQOROS. 

(Aft E rNutta-u_I9I|) 

Fig. 80. 



Adults Attac* 
HostsTZItoN. 
When Fecundated 
AndRepleteTme 
Females Drop 
AndOviposit 



Adults Appear^ 




MALE LIVES ON 



^-uviPoaiTLONL-OMMENces. 



-'Larvae Hatch, But 
Stay In Eggs — 
TheyDoNotFeeo. 



FEMALE LIVES ON 



'"■First NyMPHAi.5TA9e 
\\ i / / EMEReesFROMLARVALiKIM 

<Si // 

TJymphal Stages Attack Hosts ItoY"- 
And Drop Off Replete 



TICKLIFECYCLE-TYPEI 

The Life Cycle ofOrnithodorosmoubataano O.savignyi. 

(AfterNuttall 1911) 



Fig. 81. 



424 SANITARY ENTOMOLOGY 



SUMMARY 



A good idea of the diversity of life cycle and of the interrelationship 
of the tick to its host and its parasite can be obtained by a comparison 
of the life cycles of Hcemogregarina canis and Babesia canis, both of 
which pass their cycle of sporogony in the dog tick Rhipicephalus san- 
guineus and their cycle of schizogony in the dog. Two charts are pre- 
sented to illustrate the life cycles of these two parasites (figs. 78, 79). 
It will be noticed that a certain tick, taking up both of these parasites in 
its nymphal stage from a given dog, would communicate the Haemogre- 
garina to its adult host, but the Babesia would not be transmitted until the 
tick's offspring had reached the adult stage, possibly on the third dog host 
of the offspring. The best way in which to understand how ticks can carry 
disease organisms is to study the types of life cycles which were worked out 
by Nuttall, and charts of which are presented. In the first type (fig. 80), 
found in various species of the genera Argas and Ornithodoros, theie 
are one larval host, two nymphal hosts, and an indefinite number of adult 
hosts. Thus, it is apparent that organisms which can be taken up by 
any one of these stages can be transmitted to quite a number of other 
hosts by the same tick. 

In type two (fig. 81) there is no larval host but there are five 
nymphal hosts and any number of adult hosts. This type is found in 
Ornithodoros moubata and 0. savignyi. It is therefore apparent that 
the diseases transmitted by these ticks can be conveyed to a number of 
successive hosts by the same tick. 

The third type (fig. 82), found in the genera Ixodes, Haemaphysalis, 
Dermacentor, Rhipicephalus, and Amblyomma, consists of a development 
with just three hosts, one for the larva, one for the nymph, and one for 
the adult. Therefore, if the parasite is taken up by the nymph it may 
be transmitted to the host of the adult, but if the parasite is taken up 
by the adult, it must either die or be transmitted hereditarily by the off- 
spring of the tick. 

Type four (fig. 83), found in Rhipicephalus evert si and Hyalomma 
agyptium, consists of a development with only two hosts. The larva 
develops into a nymph on the host and the nymph drops when replete. 
It reattaches as an adult. The possibilities of transmission are similar 
to those in type three, but tend more toward hereditary transmission. 

Type five (fig. 84), represented by the genus Boophilus, has only 
one host. The larva attaches and goes through its entire transformation 
on the host. It is, therefore, apparent that any organism transmitted 
by these ticks must be transmitted hereditarily. 

Type six (fig. 85) is similar in that there is but one host. It is repre- 
sented by Ornithodoros megnini, which is on the host during its larval 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 425 



J& 


2 


-. RtPLETlFECUNOATtoFEMALt 

C^ Drops FromHostM 

^^_ MALE DIES 

»^ /^\ "* OviPosinoN Commence*. 

/N^\ FEMALE D,ES 
/ \X\ "Larvae Hatch Out 


Adults Attack T [ 
Host I And \ \ / A 
Mate. \ \yS ^H 

AoultsEmerse ' N. ^^H 
From Nymphal Skin \^ /t/T^^^ 
While On Ground /<<!^PH 
/ 

/ 

RtPtprt Nymphs Drop 
From Host II 


Y^B B~~.~+~ Larvae Attack 
V^B mS Host I 

\ ^^^^r ^ / 

\ y / ^Replete Larvae 
^S\ / Drop From Host I 

__ "^ \NymphsEmergeFrom 

LarvalS kin While On Ground 
Nymphs Attack Host H 



TICKLIFECYCLE'TYPEI 

The LifeCycle of Ixodes moa«onuj, I. ricinus,I.canisu6a,Haemaphysaus leachi, H.punctata, 

DeRMACENTOR RETICULATUS, D OCtlBINTAUS.D.VARIABILIS.nHIPICEPHALUS APPENDICULAR*, 
R. SAN8WINEUS.R.SIMUS AND AmSLYOMMA HEBRAEUM. 

(After Nuttall 191 1) 

Fig. 82. 




Adults Attach- • 
Host II And 
Mate 



Aduts Emerge. 
FromNymphal 
Sk.n While On Ground /^JVVMPK 

Replete Nymphs 
Drop From Host I 



/ Replete FecundatedFemalE 
Drops From Host D. 
MALE DIES 

^ — Oviposition Commences. 
FEMALE DIES. 

Larvae Hatch Out 



"Larvae Attack 
Host I And 
Remain Thereon 
When Replete 



Nymphs Emerge From 
Larval Skin On Host I 
And Reattach. 



TICK LIFE CYCLE-TYPE E 

TheLifeCycieofRhipicephalusevertsi andHyalomma aegyptium. 

(Atter Nuttall. I9ll) 

Fig. 83. 



426 



SANITARY ENTOMOLOGY 



AoultsEmmkte 
From Nvmpmau Skin 
On Host I , Rt at tag 

A no Mate 




^Replete Fecundated Female 
Drops From Host I 

MALE DIES 
— Opposition Commences. 
FEMALE DIES. 
Larvae Hatch Out 



•LarvaeAttack 
Host I An© 
RemainThereon 
ac f When Replete. 



Nymphs Emerge From 
Larval Skin On Host I 

Ano Reattach, Remain ini 

When Replete 






TICK LIFE CYCLE-TYPE V 

The Life Cycle ofThegenus Boophilus 

(After NuttallI9I|) 

Fig. 84. 



Adults Emerge And^' 
Mate Without Feeding 



After Several Moults 
On HostI The Nymph, 
When Replete Drop 




---Ovipos'tion Commences 
--Larva Hatch Out 



Larva Attack 
Host I, And 
When Replete 
Remain 



flRST NYMPMAuSTAOt 

Emerges From Larval Skin 
And Reattaches. 



TICK LIFE CYCLE =TYPE1 

* The Life Cycle ofOrnithodoros megniimi. 
[Original.) 

Fig. 8.5— (Pierce). 



DISEASES CAUSED OR CARRIED BY MITES AND TICKS 427 

and nymphal stages, and does not reattach during the adult stage. The 
organism, if taken up, must be taken up by the larva or nymph and 
remain in the body during transformation, entering the eggs, thus to be 
transmitted by the offspring of the tick. 

It is quite evident from this that any one who studies the trans- 
mission of disease by ticks, must first take into account the life cycles 
of the ticks which he is studying, in order to arrive at any understanding 
of the life cycles of the parasites. Perhaps we may learn a valuable lesson 
from the ticks in our search for the life cycles of parasites in other forms 
of invertebrates. 

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Brumpt, E., 1908.— Bull. Soc. Path. Exot., vol. 1, pp. 577-579. 
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Castellani, A., and Chalmers, A. J., 1913. — A Manual of Tropical Medi- 
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428 SANITARY ENTOMOLOGY 

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48 pp. 
Mollers, B., 1907.— Zeitschr. f. Hyg. u. Infekt.-Krankh., vol. 58, pp. 277- 

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Nuttall, G. H. F., 1904.— Lancet, vol. 167, pp. 1785-1786. 
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Theiler, A., 1905.— Transvaal Dept. Agr., Rept. Govt. Vet. Bact., 
1903-1904. 

Theiler, A., 1908.— Transvaal Dept. Agr., Rept. Govt. Vet. Bact., 
1906-1907. 

Theiler, A., 1909.— Transvaal Dept. Agr., Rept. Govt. Vet. Bact., 
1907-1908. 

Theiler, A., 1910.— Transvaal Dept. Agr., Rept. Govt. Vet. Bact., 
1908-1909. 

Theiler, A., 1910.— Bull. Soc. Path. Exot., vol. 3, pp. 135-137. 

Von Prowazek, S., 1912-1914. — Handbuch der Pathogenen Protozoen. 

Valladares, J. F., 1914.— Parasitology, vol. 7, No. 1, pp. 88-94. 

Valladares, J. F., 1915. — Parasitology, vol. 7, pp. 88-94. 

Wilson, L. B., and Chowning, W. M., 1902. — Journ. Amer. Med. Assoc, 
vol. 39, July 19, pp. 131-136. 

Wolbach, S. B., 1919. — Journ. Med. Res., Boston, vol. 41, No. 1, Novem- 
ber, pp. 1-193, plates 1-21. 



CHAPTER XXX 

The Biologies and Habits of Ticks * 
F. C. Bishopp 

The importance of ticks as vectors of disease and as simple parasites 
has directed the attention of many workers to this group. Although the 
superfamily Ixodoidea, which comprises the ticks, is comparatively small, 
the species numbering about 300, the life-histories and habits of the 
species are quite varied. Many forms exhibit a close correlation between 
their habits and habits of their hosts. There is often also a marked rela- 
tionship between seasonal and climatic conditions and the presence and 
abundance of different species. 

Knowing the intimate interdependency between ticks, their hosts, and 
several serious diseases of man and animals, and also considering the 
fact that all important control measures are based upon the life histories 
of the species concerned, we cannot too strongly emphasize the need 
of a thorough knowledge of host relations, distribution, and life histories 
of the more important species. 

Stages in the Life of Ticks. — There are two distinct families com- 
prising the ticks. One of these, known as the Argasidae, may be recog- 
nized by the absence of any highly chitinized parts, while the other, the 
Ixodidae, is supplied with a definite, highly chitinized scutum or shield (on 
the dorsum anteriorly), and highly chitinized legs and other parts. 

There are usually four distinct stages in the life of all ticks. The 
Ggg, which is more or less oval in shape and usually brown in color, the 
larva or six-legged stage, the nymph or second stage (with eight legs), 
and the adult tick in which the sexes are well defined. In several species 
we have a second or even third nymphal stage. In the Ixodidae the males 
and females are usually readily distinguished in the unengorged state. 
The female has a chitinized shield covering almost the entire dorsal side. 
In this group of ticks the female is the only one which becomes greatly 
distended with blood, and being quite conspicuous when engorged, is the 
form usually observed by the layman. In practically all the species the 
males attach and imbibe some blood, but do not become greatly swollen. 

Habits. — There are certain general habits which are peculiar to the 
two families of ticks. Most species in the family Argasidae remain free 
1 This lecture was prepared for this edition only. 

430 



THE BIOLOGIES AND HABITS OF TICKS 431 

from the host the greater part of the time, imbibing blood rapidly when 
favorable opportunity offers, such as when the hosts are at rest at night. 
The first or seed tick stage of this group of ticks, however, usually remains 
on the host for several days. The adults of this family partake of blood 
meals several times and the females deposit a number of batches of eggs. 
The total number of eggs deposited is usually much smaller than in the 
case of the ticks in the other family. 

Among the Ixodid ticks we find but one species which has the habit 
of feeding rapidly, as in the Argasidae. In the other species each stage 
remains on the host for at least several days. Even in the same genus, 
however, we find widely different habits as regards feeding. There are 
some forms in which the larvae and nymphs leave the host for molting. 
In several species molting takes place on the host and the tick does not 
drop off until it has become replete as an adult, while in still other 
instances, the first molt takes place on the host and the second on the 
ground. In all cases in this family the engorged females deposit a large 
number of eggs and die soon after. In most species copulation takes place 
on the host. The males may remain some time after the females have 
dropped. In certain species of the genus Ixodes, however, it appears that 
the males never attach to the host, but remain in the places frequented 
by the host and when the females drop off they are fertilized by them. 
A few species have been found to deposit fertile eggs without the inter- 
vention of the male. The eggs of practically all Ixodids are deposited in 
a single mass in some protected place. They hatch almost simultaneously 
in a few weeks' time and the larvae or seed ticks usually crawl upon vege- 
tation and there await the passing of a suitable host. In the case of those 
species which drop from the host for each molt, sometimes spoken of as 
three-host species, it is necessary for the ticks to secure a host on three 
different occasions, hence undoubtedly increasing the mortality before 
maturity is reached. 

Many species show a predilection for attachment to certain regions 
of the host. Structure or habits are sometimes modified to fit the condi- 
tions under which the ticks live on the host. There is a tendency with all 
ticks to choose the more tender portions of the skin upon which to attach. 
Hence with many of our common forms we find groups of ticks between 
the forelegs, on the brisket or the inguinal region. The habit of attaching 
in the ears has already been mentioned in connection with Orntthodoros 
mcgnini (Duges) Neumann. The tropical horse tick. Dermacentor nitcns 
Neumann, also has this habit well developed. The Gulf Coast tick, Am- 
blyomma maculatum Koch, is usually found in the ear but never in the 
deeper portions of that organ. On small animals there is also frequently 
exhibited a tendency of the ticks to attach in the region where they are 
least in danger of being destroyed by scratching or biting. 



432 SANITARY ENTOMOLOGY 

Host Relations. — Ticks develop upon a great variet}^ of species among 
the higher animals. Toads, lizards, snakes, and turtles are infested to a 
considerable extent, birds are attacked by a number of species and espe- 
cially by immature stages of forms which when mature attack larger 
animals. Practically all mammals, from the small field mice to the pachy- 
derms, ruminants, and man, are infested by ticks. In general those ticks 
which remain on the host for their molts attack fewer species of animals 
than those forms which pass their molt on the ground, and nearly all 
ticks attack more than one host, but many species develop successfully 
only on certain related animals. These points are made use of largely 
in practicing control or eradication. 

Relation Between Stages and Disease Transmission. — In connection 
with the transmission of disease, the infective stages of ticks vary with the 
species and the disease organism concerned. In the case of a number 
of diseases, the organism passes from one generation to the other through 
the egg. This is true in the case of the cattle tick and Texas fever and 
also with Rocky Mountain spotted fever. With certain diseases the< 
adults only are infective and these derive the infection from the adult of 
the preceding brood. Some disease organisms are taken up by the larvae 
and transmitted by the nymphs or adults of the same generation. 

Life History and Habits. — Owing to the wide diversity in life history, 
habits, and economic considerations among the ticks, it is thought best to 
briefly outline some of the principal points along this line, treating the 
matter according to species. 

The Fowl Tick, Argas persicus (Fischer Von Waldheim) miniatus 
Koch (plate XXVI). — This is a serious pest of various kinds of poultry 
and is tropicopolitan in distribution, usually being most abundant in the 
semi-arid regions. In the United States it occurs in Florida, and from 
Central Texas westward to the Pacific. It not only acts as a simple para- 
site but is responsible for the transmission of a disease of fowls known 
as spirochaetosis. It has been reported as attacking man, but can not be 
considered of any special importance in this regard. 

The seed ticks remain attached to the fowls from four to ten days, 
dropping at night and spending the remainder of their life hidden away 
about the roosting places of the fowls, only venturing out to feed at 
night. Several batches of eggs are deposited, engorgement taking place 
after each deposition. These ticks are remarkable on account of the fact 
that they can live over two years without food. They are also very 
resistant to insecticides. 

There is another species of Argas A. reflexus (Fabricius) Latreille, 
which is of considerable economic importance. This attacks pigeons, 
Most of the other members of this genus feed upon birds and bats. 

The African Relapsing Fever Tick: Ornithodoros moubata (Murray) 



THE BIOLOGIES AND HABITS OF TICKS 



433 



Pocock. — This tick is a common parasite of man in a large part of tropi- 
cal Africa.. It also feeds on domesticated animals. It lives in the huts 
and is carried about by the natives in their mats, etc. As the name 
indicates, it is the carrier of relapsing fever or tick fever of man in 
Africa. The tick hides and breeds in the cracks, feeding at night. This 




Plate XXVI. Fig. 1 — (Upper left) Larvae of fowl tick under feathers of chicken. 
Fig. 2 (Upper right) — Un en gorged male. Fig. 3 (Lower left) — Female with eggs. 
Fig. 4 (Lower right) — Unengorged female. 



species is peculiar in that it does not have an active seed tick stage, 
the first molt taking place within the egg shell. 

The Spinose Ear Tick, Ornithodoros megnini (Duges) Neumann. — 
This is an American species. It is an important pest of live stock in the 
semi-arid Southwestern United States and throughout Mexico. It also 
occurs in the ears of certain wild animals and not infrequently attacks 
man, producing severe earache. The tick normally attacks deep in the 
ears of the host. The first or larval stasje is very active. This is the 



434 SANITARY ENTOMOLOGY 

stage which enters the ears. The larvae molt to nymphs within the ears in 
from seven to twelve days. The nymphal stage is covered with spines, 
hence the common name. Engorgement in this stage requires from 31 to 
over 200 days. The nymphs then crawl out of the ears, hide about barns, 
posts, trees, etc., and molt their skins, copulate, and lay eggs, no food 
being taken in the adult stage. The eggs are deposited in these hiding 
places and the larvae remain on the objects until brushed off by an animal. 

There are several other species in this genus, some of which are of 
importance as parasites of man and animals. One which is common 
in the Southwest infests the burrows of prairie dogs and other wild rodents 
and may attack man at night. The species 0. savignyi (Audouin) KocK 
is widely distributed in Africa and southern Asia. It normally feeds on 
the camel but often attacks man. Certain other species in the tropics 
of Asia bite man, but the transmission of disease has not been definitely 
connected with them. 

In the family Ixodidae there are many important species. Only a few 
will be mentioned. 

The Castor Bean Tick or Black-Legged Tick, Ixodes ricmus (Lin- 
naeus). — This species is common throughout the greater part of Europe 
and Asia and two varieties of it occur in the United States. The mouth- 
parts are long, thus often producing a troublesome bite. The hosts 
are many, including both domestic and wild animals and man. While it 
has not been connected with any disease in America, it has been clearly 
shown to carry red water or bovine piroplasmosis in Europe. This tick 
drops from the host to molt, the larvae engorge in from three to nine days 
and molt in three to four weeks. The period of engorgement of the 
nymphs is practically the same as in the larvae. The nymphs require some- 
what longer to molt to adults. The females require about eight to fifteen 
days to become engorged, and begin depositing eggs in about two weeks. 
The eggs hatch in from forty days to several months. 

The Genus Haemaphy satis — H. leachi (Audouin) Neumann, which is 
common in Africa, has been shown to carry malignant jaundice (Babesia 
canis) of dogs. The common rabbit tick in the United States belongs 
to this group. Another species H. cinnabarina (Koch) punctata Canes- 
trini and Fanzago is sometimes of importance as a parasite on catttle, 
sheep, and other domestic animals. All of the ticks of the group drop 
for molts, and the developmental periods are somewhat similar to those 
outlined for Ixodes ricinus, with the exception of the species H. inermis 
Birula, which occurs on deer in Europe. The immature stages of this 
tick engorge very rapidly, becoming replete in from l 1 /^ to 24 hours. 

The Cattle Tick, Boophilus annulatus (Say) Stiles and Hassall 
(Margaropus) (plate XXVII) and Varieties of This Species. — This is 
probably the most important tick in relation to live stock. B. annulatus 



THE BIOLOGIES AND HABITS OF TICKS 



435 



proper occurs in southern United States and parts of Mexico while 
varieties of this species are present in tropical America, Africa, Australia, 
and other parts of the world. It is not only a species which produces heavy 
losses on account of its occurrence in tremendous numbers, but it is espe- 
cially important on account of being the intermediate host of the piro- 
plasma which produces Texas or splenetic fever in cattle. 

Our form is very restricted in host relations. It can complete develop- 
ment only on cattle, horses, mules, and deer, rarely on a few smaller ani- 
mals. This habit has greatly facilitated eradication. The molts are 





Plate XXVII. — The cattle tick, Boophilus annxdatus. Fig. 1 (Left) — Fully engorged 
female. Fig. 2 (Right) — Engorged female depositing eggs. (Bishopp.) 



passed on the host. The females deposit from 2,500 to 4,500 eggs. In 
summer these hatch in from 20 to 30 days, while in the fall and winter 
the incubation period may extend to 200 days. The longevity of the seed 
tick varies according to temperature and humidity from about two to 
eight months, and the period from dropping of the engorged female to 
the death of all of her progeny, or the nonparasitic period, ranges from 
28 days in summer to 279 days in cooler weather. The period of attach- 
ment of the seed tick to the host until the engorged female detaches 
ranges from 20 to 59 days. Both of these periods are of considerable 
importance in connection with control by the so-called pasture rotation 
methods. 

The Genus Rhipicephalus. — This group, though small, contains many 



436 SANITARY ENTOMOLOGY 

species of importance. The species are most abundant in Africa where 
several of them are connected with the transmission of disease. R. appen- 
diculatus Neumann is the principal transmitting agent of East Coast 
Fever, a malignant disease of cattle in Africa, and four other related 
species play some part in the dissemination of this malady. R. evertsi 
Neumann is credited with the transmission of Nuttallia equi, or biliary 
fever of equines, in South Africa. R. bursa Canestrini and Fanzago trans- 
mits Babesia ovis of sheep in southern Europe and R. sanguineus 
(Latreille) Koch, a species which is present in extreme southern Texas 
and Florida and generally distributed throughout the tropical parts of 
the world, plays some part in the transmission of babesiasis or malignant 
jaundice of dogs. The biologies of the ticks in this group are quite simi- 
lar to that outlined for Ixodes and need not be repeated. With most 
species the molts are passed off the host. R. bursa, the sheep tick, and 
R. evertsi, the horse tick, of South Africa, are exceptions, the larval 
molt being passed on the host and the nymphal molt on the ground. F'or 
the most part, the ticks of this group are general feeders. 

The Genus Amblyomma. — This group reaches its maximum develop- 
ment in South America. In the United States we have three species of 
some economic importance. The Lone Star tick, A. americanum Linnaeus, 
is the commonest of these. It is widely distributed through the country 
and extends into South America. The females are readily recognized by 
the single white spot on the scutum, from which the common name is 
derived. All of our species are general feeders and attack man freely 
but are not known to carry disease. In tropical America, A. cajennense 
Fabricius is tremendously abundant and is often the cause of much annoy- 
ance to man, the larvae and nymphs attaching to the skin by the hundreds 
and frequently ulcerated sores develop from scratching. The best known 
species of this group all drop from the host to molt. Engorgement of 
the different stages is comparatively rapid, ranging from three days to 
three weeks. The Bont tick, A. hebraeum Koch, a South African species, 
is capable of carrying the disease known as heart water of sheep. Louns- 
bury's studies indicate that the organism of this disease does not pass 
through the egg but is taken up by the larvae or nymphs and subse- 
quently transmitted by the following stage. 

The Genus Dermacentor. — This group reaches its highest develop- 
ment in North America. About half of the species drop from the host 
to molt while the others pass the molts on animals. The most important 
species economically is the Rocky Mountain spotted fever tick, D. venustus 
Banks (or D. amdersoni Stiles of many authorities 2 ). This species drops 

2 The editor has ehosen to adopt andersoni as the name for the Rocky Mountain 
spotted fever tick on the grounds of priority and absolute identification. (See footnote 
on this species in Chapter XXIX, p. 409.— W. D. Pierce. 



THE BIOLOGIES AND HABITS OF TICKS 437 

from the host to molt and is a very general feeder in the immature stages, 
practically every rodent of the region being attacked. The species is 
widely distributed in the Rocky Mountain and intermountain region, 
but the disease of man which it carries is somewhat more limited in range. 
In the Bitter Root Valley in Western Montana occurs the most virulent 
form of the disease. Investigations conducted b}^ the Bureau there, 
indicate that the adult ticks develop almost exclusively on the larger 
domestic animals and this point has been utilized in control. In other 
regions, however, the jack rabbit plays a considerable part in the engorg- 
ing of adults. This species is commonly known as the "wood tick" and 
in the region where spotted fever is not known it is considered of little 
importance, although occasionally it becomes so abundant as to injure 
live stock through irritation and blood loss. It also occasionally produces 
a form of paralysis in man and animals. 




Fig. 86. — The Rocky Mountain Spotted Fever Tick, Dermacentor andersoni (Bishopp.) 

The larvae are comparatively short lived but the nymphs and adults 
live for many months. In fact it is possible for individual ticks which 
have access to hosts in the nymphal stage to live so long as to carry 
the species over three years. The larvae develop on the animals in from 
three to eight days and these molt their skins in from one to 
three weeks. The nymphal engorgement is practically the same as in 
the larval stage, but the molting requires from eleven days to two 
months or even longer. The females become filled with blood in from one 
to three weeks. From 4,000 to 7,000 eggs are deposited. The winter is 
usually passed in the nymph and adult stages, and these stages, espe- 
cially the adult, are markedly active in the spring months. Seldom are 
any of the adults to be seen on hosts after the middle of July, and practi- 
cally all cases of spotted fever occur in March, April and May. The 
disease may pass from one generation to the next through the egg and 
all stages are capable of transmitting the malady. However, the imma- 
ture stages are seldom found on man and only occasionally on the large 
domestic animals. 



438 SANITARY ENTOMOLOGY 

The species is very variable in abundance, wooded or brushy lands 
being most favorable for it, particularly when close to cultivated fields, 
and of course where small mammals are present upon which the immature 
stages may engorge, and domestic animals for the engorgement of the 
adults. 

Other species of Dermacentor include the American dog tick, D. varia- 
bilis (Say) Banks, which occasionally attacks man, and the Pacific Coast 
tick, D. Occident alis (Marx) Neumann, which infest various hosts, includ- 
ing man, in the Pacific region. The life histories of these species are 
quite similar to that of the spotted fever tick. Many animals serve as 
hosts, especially for the immature stages. 

The winter tick or elk tick, D. albipictus Packard, is a representative 
of the group which remains on the host to molt. This form is often a 
serious pest of horses and cattle and is probably the cause of the death 
of many elk on account of its occurrence in great numbers on the animals 
during the winter season. The eggs hatch in the summer or late fall and 
the ticks attach in the long winter coat of the host, becoming mature 
and detaching in one to three months. 

In tropical America another species of Dermacentor, D. nitens Neu- 
mann, is often the cause of considerable annoyance to horses by its 
attack of that host deep in the ears. 

It was first suggested that a simple scheme for the separation of the 
more important species by morphological characters, host, and distribu- 
tion might be desirable, but on further consideration this idea was 
dropped. In the first place;, it is very essential, especially in considering 
disease transmission, that the exact species of the possible vector be 
determined. This can always be accomplished best by submitting speci- 
mens to a specialist. In the second place there is a general lack of 
familiarity among sanitarians and even among entomologists with ticks 
and the characters utilized in distinguishing different forms. 3 

In collecting specimens it is well to attempt to secure both sexes. The 
males are usually rather smaller and less conspicuous than the females, 
especially when the latter are engorged. The specimens may be preserved 
in 70 per cent alcohol or 3 per cent formalin solution. 

BIBLIOGRAPHIC REFERENCES 

Literature on ticks has become quite voluminous. Fortunately there is 

a very complete . bibliography available. This appeared in two parts, 

3 The writer (Box 208, Dallas, Texas) is prepared to make determinations of the ticks 
of North America on short notice. In Europe there are a number of systematists in 
this group. Dr. G. H. F. Nuttall of Cambridge University, Cambridge, England, would 
no doubt be glad to determine specimens sent to him. Professor L. G. Neumann, 
Laboratorie d'Histoire Naturelle, Toulouse, France, is a leading tick authority on the 
continent. Prof. C. P. Lounsbury, Pretoria, South Africa, is well acquainted with the 
ticks of that region. 



THE BIOLOGIES AND HABITS OF TICKS 439 

July, 1911, and May, 1915, as a part of "Ticks. A Monograph of 
Ixodoidea" by Nuttall, Warburton, Cooper, and Robinson (Cambridge 
University Press). Those who wish to go into the systematic or biologic 
studies of ticks further should consult the monograph above mentioned. 
Three parts of it have been issued. These cover the Argasidae and the 
genera Ixodes and Haemaphysalis. Dr. Nuttall has also published a 
number of important papers on habits and notes on biologies of the 
ticks. Most of these appeared in the Journal of Parasitology, Cambridge. 
In South Africa, Prof. C. P. Lounsbury has done a large amount of 
work, especially on the biologies of ticks. Many of his articles appeared 
in the Agricultural Journal of Capetown, in the Transvaal Agricultural 
Journal, and in the reports of the Government Entomologist, Cape of 
Good Hope Department of Agriculture. A summary of Prof. Neumann's 
systematic work with descriptions and tables for differentiating species 
has been published as "Ixodidae" (in Das Tierreich, 26 Lieferung, pub- 
lished by T. E. Schulze, in Auftrage der K. Preuss. Akad. d. Wiss., Berlin, 
1911. R. Friedlander & Sohn). In the United States the principal papers 
are a "Revision of the Ixodoidea" by Nathan Banks, 1908, Bureau of 
Entomology, Technical Series, Bulletin 15, and several papers on tick 
biologies by Hunter, Hooker, Bishopp, and Wood, the most important of 
these being issued as Bulletin 106 of the Bureau of Entomology. 



CHAPTER XXXI 

Control of Ticks x 
F. C. Bishopp 

Methods of destroying ticks may be divided into two general heads — 
starvation and destruction with insecticides. The former is much more 
limited in its practical application owing to the long life of many species 
of ticks and the fact that many of them are capable of developing on a 
number of different hosts. Furthermore, destruction with chemical agents 
appeals to most stockmen owing to the fact that they can actually see 
the destruction of individuals* 

Knowing the ill effects produced by tick infestation, both through 
blood loss and the irritation due to gross infestations and by disease trans- 
mission, one would think there would be little difficulty in inducing people 
to proceed with control or eradication measures. However, this is not 
the case. In practically all parts of the world it has been found that 
stockmen will attempt to destroy ticks when they become grossly abundant 
but their efforts relax when the numbers are reduced to a considerable 
extent. In this connection it might be well to mention some of the benefits 
which are derived from tick control or eradication. By keeping the 
number of ticks reduced to a minimum, the growth of animals and the milk 
flow in cattle are increased. Death loss through gross infestation is 
avoided and, by accomplishing eradication, several of the most dangerous 
diseases of live stock and some of those of man would disappear. This 
would permit of more rapid agricultural development of many regions 
of the world. 

By following either the method of repression or eradication, the bring- 
ing under control of the herds of live stock is an important consideration. 
This is greatly facilitated by fencing and clearing of brush lands. Clear- 
ing also has a direct influence on the abundance of ticks, as the worst 
infestations in the case of many species are to be found in lands more or 
less covered with woods and brush. 

It is important in many instances to maintain effective quarantines 

to prevent the uncontrolled movement of stock and the consequent spread 

of the ticks which transmit disease. The effectiveness of this procedure 

has been fully demonstrated by the result of the quarantine maintained on 

1 This lecture was prepared especially for this edition. 

440 



CONTROL OF TICKS 441 

tick-infested cattle in our Southern States. This has prevented the ravag- 
ing of the nonimmune cattle of the Northern States by this disease, and 
also has the effect of hastening the eradication of the tick in the South. 
In South Africa quarantines are doing much to reduce the losses produced 
by East Coast fever, but there the control of the movement of man from 
infected to uninfected areas is also needed, though not easily enforced. 
The infected ticks may also be shipped in hay cut on infected meadows. 

With many species of ticks which have the habit of developing in one 
or more stages on wild animals, the question of the destruction of such 
hosts is at once apparent. Fortunately in the case of our cattle tick 
in the Southern States these wild animal hosts play a very unimportant 
part in the maintenance of an infestation, and, in the instance of the 
Rocky Mountain spotted fever tick and a number of ticks concerned in 
transmitting East Coast fever of Africa, and other species, much can be 
accomplished by the systematic treatment of domestic animals with little 
attention being given to the destruction of native hosts. However, with 
the majority of species the control, and especially eradication, can be 
facilitated by the destruction of wild hosts. 

Since the procedure necessary to accomplish the destruction of ticks 
must be varied according to the habits of the species concerned, the dis- 
cussion will now be taken up by species. 

The Cattle Tick, Boophilus annulatus, and Varieties of the Species. — 
The accomplishment of our own Department of Agriculture in the eradica- 
tion of this tick in the Southern States is especially notable and pre- 
sumably familiar to all. In this eradication work, which has been carried 
on by the Bureau of Animal Industry, the dipping of cattle has been 
relied upon almost exclusively. However, since it is both possible and 
practical to accomplish eradication of this species by the starvation plan 
and since this method may be utilized in a practical way, in combating 
other species, those concerned with tick control should become familiar 
with the principles involved. The system is dependent essentially upon the 
proper division of the farm by fences usually placed 10 or 15 feet apart 
to avoid infestation from one field to another, and the knowledge of the 
time required both for ticks to complete development on the host and for 
the seed ticks to die from starvation under different seasonal conditions 
when proper hosts are not present for them to feed upon. By various 
modifications of the plan the cattle and certain fields on the farms may 
become tick free in from 4!/2 to 9 months. The entire farm will be tick 
free in from 131/2 to 15 months. 

Destruction of ticks by the use of chemicals has been practiced for 
many years and hand dressings with various decoctions have been resorted 
*to in reducing gross infestations. Spraying is practiced where but few 
animals are treated, but dipping must be relied upon if large numbers of 



442 SANITARY ENTOMOLOGY 

animals are to be treated, or if complete destruction of ticks is to be 
accomplished. 

Dipping vats of various designs and built of several kinds of material 
have been utilized. The size of course is dependent somewhat on the num- 
ber of animals to be treated. The question of vat construction is dis- 
cussed in several bulletins of the Department and these should be consulted 
by those contemplating vat building. 

In the early days of tick control work crude petroleum was utilized 
almost entirely against the cattle tick, but this had many disadvantages. 
At present arsenicals are relied upon exclusively. These consist of either 
sodium or potassium arsenite. The usual formula used in making up 
the dip is as follows: Sodium carbonate (sal soda) 24 pounds, arsenic 
trioxide (white arsenic) 8 pounds, pine tar one gallon, and water to make 
500 gallons. Under certain conditions a stronger dip, consisting of 25 
pounds of sal soda and 10 pounds arsenic, is used. A concentrated or 
stock solution is made by dissolving the sal soda in about 25 gallons of 
water, adding the white arsenic and boiling until it is all combined; then 
after cooling the dip to about 140° F. the pine tar is slowly added while 
stirring. 

Several modifications of this dip and methods of making it have been 
introduced, among them the addition of caustic soda to produce the com- 
bination of the arsenic and sal soda without boiling. The self-boiled 
dip is prepared in two parts which should not be combined except in the 
diluted condition in the vat. These are the arsenic stock and the tar 
stock. The arsenic stock is made as follows: Caustic soda (at least 85 
per cent pure, dry, granulated) 4 pounds, white arsenic (99 per cent 
pure) 10 pounds, sal soda (crystals) 10 pounds. In a large metal con- 
tainer place the 4 pounds of caustic soda, add one gallon cold water and 
stir until the caustic is practically all dissolved. Immediately begin add- 
ing white arsenic, a pound or two at a time as fast as it can be dissolved 
without causing boiling. If the mixture begins boiling stop stirring and 
cool slightly before adding more arsenic. If the proper kind of chemi- 
cals are used a clear solution, except for dirt, should result. When the 
solution is cool add cold water to make 5 gallons. This stock solution 
may be used immediately or kept indefinitely. The tar stock is prepared 
by dissolving % of a pound dry caustic soda in 1 quart of water, add 
1 gallon pine tar and stir until a uniform fluid resembling molasses 
results. It should mix perfectly with water. In filling the vat, first add 
the necessary amount of water then add the concentrated dip in a thin 
stream in various parts of the vat. The tar stock should be mixed with 
several times its volume of water before being added to the vat. Stir the 
mixture in the vat thoroughly. 

Another modification of this dip which should be mentioned is the 



CONTROL OF TICKS 443 

addition of soap and kerosene oil. This was devised by Watkins-Pitchford 
for the frequent dippings necessary to destroy ticks in South Africa. It 
has been utilized also by the Bureau of Entomology in the weekly dip- 
ping of animals against the spotted-fever tick. The destructive effect 
of the material on the tick is increased and the caustic action on the 
host is reduced by this addition. This formula is as follows, English meas- 
ure: Arsenite of soda (80 per cent arsenious oxide) 8% pounds, soft 
soap 5% pounds, paraffin (kerosene oil) 2 gallons, water 400 gallons. 

It is important that the proper strength of the solution be main- 
tained at all times, both to secure efficiency in tick destruction and to 
avoid injury to the stock. A simple outfit has been devised by the U. S. 
Bureau of Animal Industry for determining the percentage of arsenic 
present. 

To accomplish the eradication of the cattle tick the frequency of 
dipping is important. It should never be longer than the period required 
|or the ticks to become mature and drop from the host. This is about 
20 days. Usually it is safer to dip at intervals of two weeks. Eradication 
may be accomplished if systematic dipping of all stock is kept up for a 
period of about six months in the summer, or sufficient time to allow all of 
the seed ticks which have not gained access to the host to die of starva- 
tion. Thorough dipping of every individual is important ; the animals 
should be completely submerged. 

Owing to the poisonous effect of arsenicals, both when taken internally 
and under certain conditions when applied externally, the following pre- 
cautions should be exercised in dipping live stock. Have the bath of the 
proper strength, water the animals a short time before dipping, avoid 
heating the cattle by long drives or otherwise just before or after dipping, 
dip during the cool part of the day or provide shade when convenient. 
The latter point* is not nearly so important in connection with the use of 
arsenicals as with oil dips. The poisonous effect of arsenicals has been 
mentioned in dealing with the control of cattle lice. It need not be dwelt 
upon further here. It is certain that dipping in arsenical solutions is 
the most satisfactory method of destroying ticks and lice of all kinds on 
cattle and horses, and the experience of stockmen in the South in con- 
nection with the cattle tick eradication indicates that, if the proper 
precautions are exercised, thousands of cattle may be dipped without the 
loss or injury of even a single animal. 

The Rocky Mountain Spotted Fever Tick. — As was pointed out in 
the lecture upon the biologies of ticks this species has the habit of drop- 
ping from the host for each of its molts. It also develops on a large 
number of different species of animals, but the adults, especially in the 
Bitter Root Valley where the disease is the most virulent, practically all 
engorge on the larger domestic animals. This species appears to be 



444 SANITARY ENTOMOLOGY 

somewhat more resistant to arsenical dips than the cattle tick, and it 
was found best to add kerosene emulsion to the arsenical, following the 
Watkins-Pitchford formula. In order to prevent the dropping of replete 
females, the dipping must be practiced at weekly intervals. Fortunately 
the spotted fever tick confines its activity in the adult stage to the spring 
months, so that it is not necessary to continue the dipping later than 
about the first of July. 

Since practically all of the immature stages of this species develop 
on small rodents, notably the ground squirrels, wood rats, pine squirrels, 
rabbits, etc., the importance of rodent destruction, both from the stand- 
point of tick control and protection of crops, is apparent. In much of 
the territory where the spotted fever tick abounds, it is, however, impracti- 
cable to reduce the number of rodents to a very low point. In other 
words, in the scheme of eradication dipping of live stock should come 
first and the destruction of rodents be taken up as a secondary step. 

Aside from the destruction of this tick on animals, it is necessary for 
man to protect himself against its attack. This can be accomplished to 
some extent by avoiding cut-over woodlands or brushy areas, by wearing 
clothing calculated to exclude the ticks and by examination of one's 
person at frequent intervals. It was found by Dr. Ricketts that a tick 
must be attached to a guinea pig for one hour or longer to produce the 
disease, thus it would seem that there is little danger of infection in man 
if the ticks are removed promptly. Since no successful remedy for the 
treatment or prevention of the disease has been devised, the importance 
of exercising care in preventing infection by keeping free of ticks can not 
be too strongly emphasized. 

The Spinose Ear Tick. — We are concerned with this species both on 
account of its injurious effect on horses, cattle, dogs, and other animals, 
and the frequency of its attachment in the ears of man. Furthermore we 
should be familiar with this tick since a considerable part of our military 
activities in this country have been and will probably continue to be iii 
the Southwest where the species abounds. 

It is probable that by exercising some care in locating camps and in 
choosing places for sleeping, some degree of immunity from attack will 
result. The seed ticks are, of course, concentrated about feed lots, 
corrals and watering places of live stock and these should be avoided in 
choosing a camp site. 

The effect on animals of heavy infestations of this species is very 
marked. The ears are droopy, the hair rough and the animal presents 
an unthrifty appearance. Fattening is difficult if not impossible, and 
under range conditions the loss by death is not infrequent. In horses and 
mules there is a marked shyness on the part of the animals when attempt 
is made to touch the ears or put on a bridle. This is sometimes so extreme 



CONTROL OF TICKS 445 

that it is almost impossible to halter or bridle an infested animal. In 
man there are seldom more than one or two ticks present, yet the pain is 
described as excruciating at times, and a sensation of tickling, ringing, 
and fulness at others. The ticks are usually so far in the ear that they 
can not be discerned readily from the outside and hence frequently they 
are overlooked for weeks. 

In man the removal of the ticks with forceps will usually give complete 
and permanent relief. In horses and cattle mechanical removal with a 
rather blunt instrument may be practiced, but in general it is better to 
depend upon the application of some material to destroy the ticks. 
Unfortunately the dipping of live stock in the ordinary tickicides will not 
reach or destroy this species, hence we must depend upon individual treat- 
ment. The Bureau of Animal Industry (Farmers' Bulletin 980) has 
found that a mixture of pine tar and cottonseed oil (2 to 1) will destroy 
all ticks if properly worked into the ear. It may be applied with a long- 
spouted oil can or hard rubber syringe, the base of the ear being manip- 
ulated as the material is injected. About one-half an ounce is required 
for each ear. It also has the advantage of protecting the animals against 
reinfestation for about a month. 

The Chicken Tick. — Although this is an important poultry pest, the 
comparative freedom of man from its attack will not justify a lengthy 
discussion here. While spirochaetosis of fowls, known to be carried by 
this species, appears not to be present in the United States, it is a source 
of considerable loss in many other parts of the world, in the tropics and 
subtropics. In this country the main loss is due to the weakening of 
the fowls by the loss of blood and irritation. This often is sufficient to 
completely stop egg production, reduce the fowls in flesh, and sometimes 
cause death. 

Owing to the resistance of this species to the action of chemicals, and 
on account of the habits of the species, it has been found best not to 
attempt to destroy the larvae while attached to the host but to proceed 
against the infested roosting or nesting places of the fowls. In one 
instance only is it necessary to give consideration to the individuals, and 
this is in protecting an uninfested yard or premises from introduction of 
the tick in the seed tick stage on poultry. Fowls brought in should be 
kept in quarantine in a crate or small yard for about ten days. During 
this time all of the seed ticks upon them will have become engorged and 
hidden in the roosting places and may there be destroyed by fire or some 
material as recommended for treating roosts. 

It usually pays to destroy heavily infested houses which are of little 
value. In other cases, the houses should be thoroughly cleaned and 
sprayed with the wood preservative known as carbolineum, or with crude 



446 



SANITARY ENTOMOLOGY 



petroleum (plate XXVIII). It is usually best to thin each of these sub- 
stances with one-third kerosene. Following this treatment a simple roost 
(fig. 87) should be constructed, preferably supported by four posts driven 
into the ground or attached to the floor, the roost poles being held in 
place by notches on cross bars resting in similar notches in the supporting 
posts. None of the roosts or supports should touch the walls. One or 
two applications of the carbolineum or petroleum to these roosts with a 
brush will usually suffice in destroying the infestation, although it is 
advisable to make frequent examinations to determine if all of the tick** 
are destroyed. The chicken mite Dermanyssus gallvnae is controlled by 
the same procedure. 

Other American Species of Ticks. — There are several other kinds of 




Fig. 87. — Model chicken roost (Bishopp). 



ticks of economic importance in this country. Among them should be 
mentioned the Lone Star tick which is frequently met with in the South, 
East, and Central States ; the Gulf Coast tick which produces consider- 
able irritation by attacking the inside of the external ear of horses and 
cattle in the coastal region; the tropical horse tick which is to be found 
only in extreme southwestern Texas, usually attached deeply in the ears 
of horses and mules ; and the widely distributed American dog tick which 
is sometimes sufficiently abundant to greatly annoy man and other animals. 
All of these species except the tropical horse tick, drop for their molts and 
are therefore rather difficult to control. Dipping in arsenicals, especially 
if carried out at weekly intervals, will of course reduce their numbers 
considerably. In regions where dipping vats are not generally available, 
hand picking or the application of kerosene emulsion, some of the creo- 
sote stock dips, or arsenical dips with a rag or spray pump are advisable. 
The treatment of dogs should receive special attention. The tropical 



CONTROL OF TICKS 



447 



horse tick requires local treatment similar to that for the spinose ear 
tick. 

South African Ticks. — In South Africa the so-called blue tick, a 
variety of our common cattle tick, carries bovine piroplasmosis and prob- 
ably other diseases and may be controlled by the same procedure outlined 
for our species. However, in South Africa this is not considered the most 



1 

I K 

• 

JP 


X :JA 


WjsmjBm i£w - 






jE 










I 




\W& Hi n.< 




I Ta 




. ^L- - 


nf% 


i ■■" fil 


1 






\. | . 5L* 


cj- -- ^ 


i%t?- ^ 




•*?* 


i .r^g| 







Plate XXVI II. — Spraying chicken house with oil by means of knapsack spray pump. 

(Bishopp). 



important tick parasite of live stock, since certain species of Rhipiceph- 
alus carry the much more deadly disease, East Coast fever. Since the 
immature stages of the brown tick (R. appendiculatus ) , the principal 
agent in the dissemination of the disease, become engorged and leave 
the host in three days or less, it becomes necessary to dip at very short 
intervals to prevent the escape of specimens which may infect other 
animals. The larvae or nymphs which engorge on cattle infected with 
East Coast fever are the only direct source of propagation of the disease 
in other animals, hence the main attack must be directed against them. 



448 SANITARY ENTOMOLOGY 

Watkins-Pitchford found that these stages can be killed with dip much 
weaker than is necessary to destroy the adults. He thus determined on a 
strength which would destroy these young stages with one dipping and 
yet produce no injury to the host if applied at three-day intervals. The 
adults are subjected to two dippings, as they remain on the host 7 days. 
This was found to give 100 per cent destruction. The formula (English 
measure) for this dip is: 4 pounds arsenite of soda (80 per cent arsenic), 
3 pounds soft soap, 1 gallon paraffin, 400 gallons water. The majority of 
stockmen, however, do not resort to either the three- or five-day dipping 
except when in fear of an outbreak of the disease. There is no doubt 
that by dipping at weekly intervals during the warmer period of the 
year and at intervals of two or three weeks through the cooler weather, 
if practiced consistently for two or three years, the ticks can be reduced 
to a negligible quantity, if not eradicated. 

African Relapsing Fever Tick. — While this species has received con- 
siderable attention from the disease transmission and biologic standpoint, 
little work has been done on control practices. No doubt control of the 
tick in native huts will be very difficult on account of lack of interest 
and cooperation on the part of the natives ; however, it would appear to 
be comparatively easy to protect the houses of white inhabitants from 
infestation, and for the traveler to avoid attack. The latter could be 
accomplished best by avoiding infested huts and improvising methods of 
isolation either in hammocks or otherwise. In native villages the free use 
of strong tickicides on the floors, and cleaning and airing of mats would 
undoubtedly reduce infestation and of course the provision of some 
sort of isolated bedsteads, which suggestion would probably not be taken 
up by the natives, would also prevent attack. 

The Control of Ticks in Other Parts of the World. — In Australia 
much progress has been made in the destruction of the cattle tick, but in 
other parts of the world outside of the United States little systematic 
work has been done against ticks. The hand application of insecticides 
or hand picking of adult ticks has been the principal method followed. 
No doubt many of the control practices put into effect in this country 
could be adapted to European and Asiatic conditions. 

Treatment of Tick Bites. — There are many references in literature 
and popular ideas regarding the painfulness and poisonous nature of bites 
of various species of tick. Literature contains references to deaths within 
a few hours following the bite of some tick in the region of Persia. In 
Mexico there is also an opinion entertained that certain species of Orni- 
thodoros produce very painful, if not deadly bites. In the experience of 
the writer and various other workers, most of these reports appear to be 
unfounded or exaggerated. No doubt the effect varies in different indi- 
viduals and possibly there is a relationship between the symptoms pro- 



CONTROL OF TICKS 449 

duced and the kind or health of the host upon which the tick has been 
feeding previously. Certainly some species of ticks produce forms of 
paralysis, authentic cases having been recorded as resulting from the 
bite of the spotted fever tick, and in the case of certain other species 
in South Africa and Australia. It thus appears important that tick 
bites be avoided as far as possible, and should paralytic symptoms de- 
velop, a search of the patient for ticks, especially around the occiput, 
should be made immediately. 

In regions where tick-borne diseases are known to occur, it is advisa- 
ble to treat the bite with iodine or some other antiseptic. In the absence of 
a physician, this may be done by inserting the point of a sharpened tooth 
pick or match after it has been dipped in the iodine, in the place where the 
proboscis entered. Before treatment, examination should be made to be 
sure that the mouth-parts are completely removed, as they sometimes 
break off when pulling out the tick. 

LIST OF REFERENCES 

Chapin, R. M., 1914a.— Arsenical Cattle Dips. U. S. Dept. Agr., Far' 

mers' Bull. 603, 16 pp. 
Chapin, R. M., 1914b. — Laboratory and Field Assay of Arsenical 

Dipping Fuids. U. S. Dept. Agr., Bull. 76, IT pp. 
Cooley, R. M., 1911. — Tick Control in Relation to Rocky Mountain 

Spotted Fever. Montana Agr. Expt. Sta., Bull. 85, 29 pp. 
Graybill, H. W., 1912. — Methods of Exterminating the Texas Fever Tick. 

U. S. Dept. Agr., Farmers' Bull. 489, 42pp. 
Hunter, W. D., and Bishopp, F. C, 1911.— The Rocky Mountain Spotted 

Fever Tick. U. S. Dept. Agr., Bur. of Ent., Bull. 105, 47 pp. 
Theiler, A., 1909. — Diseases, Ticks and Their Eradication. Transvaal 

Agr. Journ., vol. 7, pp. 685-699. 
Theiler, A., 1913. — Inquiry into Dips and Dipping in Natal. Agr. Journ. 

Union of South Africa, vol. 4, pp. 814-829 (1912) ; vol. 5, pp. 51-67, 

249-263. 
Watkins-Pitchford, R., 1911. — Dipping and Tick-Destroying Agents. 

Agr. Journ., Cnion of South Africa, vol. 2, pp. 33-79, with figs., July. 



CHAPTER XXXII 

Flies and Lice in Egypt * 
H. A. Ballou 

Egypt, among its other characteristics, is a land of flies. Whether 
they have been abundant there ever since the days of the plague of flies 
of Moses and Rameses may be open to argument, but there can be no 
doubt that in these times the abundance of flies is one of the things that 
strikes the visitor to the land of the Pharaohs. 

I had the good fortune to live in a small village where flies were not 
very troublesome, and that, in spite of the fact that a fairly large veter- 
inary camp was situated in the village. This camp was in charge of 
British Army officials and the village itself had been planned and built 
by a company, most of the stockholders and officials of which were 
British subjects, if not indeed actually natives of Great Britain. 

The native villages in the agricultural districts and the native sections 
of all the large cities and towns are, and I suppose always have been, 
infested with swarms of flies. This state of affairs results from the 
manner of living of the people, the nature of their religion and their 
superstitions. As to the first of these points, the Egyptians have always 
been an agricultural people, that is to say, they live on the land and by 
the land. Most of them are peasants or small proprietors, a compara- 
tively few are wealthy. In the past few years a fairly large number of 
them has become well-to-do. 

Egypt is a country practically without a rainfall. Within present 
geological time it has never been forested. The people throughout the 
whole of their history have been accustomed to live in dirt and dust, and 
they have not had wood for building houses or for fuel. They live in 
houses of sun-dried mud and they burn for fuel the manures of their 
domestic animals. 

The space available for village sites is limited to slightly elevated 
spots, which are generally too high to be irrigated and are thus useless 
for planting, and they are to some extent above the reach of flood and 
infiltration of water. Very often these mounds are the covered-down ruins 
of forgotten cities or towns. The houses are close together, often 

1 This lecture was presented to the class Oct. 7, 1918. It was written immediately 
after Dr. Ballou's return from Egypt and gives a good idea of an unsanitary nation. 

450 



FLIES AND LICE IN EGYPT 451 

there are no proper streets and the villages are walled about as a protec- 
tion against thieves and robbers. There are usually no barns or sheds for 
the animals and these are sheltered in the houses with the family or on 
the house top. 

The dung for fuel is mostly made up into small cakes and these are 
dried in the sun and stored in the houses, often in an ornamental parapet. 
For making these cakes the dung of cows and the water buffalo is used. 
This is mixed with leaves, straw, etc. Horse or donkey manure is used 
by itself, mostly as a fine dry dust to produce a quick fire for baking. It 
will be seen from this that the Egyptian has no idea that manure is 
unclean as we understand it. In the absence of rain, the Eg}^ptian village 
is always dusty and the dust is a mixture of soil, manure, and anything 
that can be dried by the fierce sun into dust. 

The Egyptian has no idea of sanitation. It is one of the commonest 
sights in all parts of Egypt where I have been, to see in the morning 
hours the men squatting in the open for their morning relief. The very 
wealthy and the residents in the larger towns and cities may have some 
form of privies, but the open field is the habitual scene of operation for 
the great bulk of the people. They have no more idea of the proper 
disposal of garbage of any sort than of the manure of their animals and 
their own ordure. 

The moisture necessary to maintain all life in these situations comes 
from irrigation canals supplied by the waters of the Nile. Every village 
is situated on or near a canal which supplies drinking water, serves as a 
place for washing clothes, for bathing, and as a place for disposing of 
anything that is to be thrown away, from a dead calf to a broken water 
vessel. 

As to the second point. One of the tenets of the Mohammedan religion 
is that the good Muslem is not allowed to take life, not even of the least 
of God's creatures. 

In connection with the third of these points, it need only be stated 
that the Egyptians are very superstitious about the Evil Eye. This 
applies particularly to the children, who must not on an} T account be 
admired or called pretty. It would be difficult to keep them clean, but 
nobody wants them to be clean. 

It is unnecessary to give details as to the degree of fly infestation that 
may be seen in a native village or in the native quarters of the towns 
and cities. The relations of flies and children may be mentioned. 

Very young children are often to be seen with their faces so covered 
with flies that it is difficult to tell the color of the child's skin. They 
swarm in the eyes, nostrils and mouth, and cover the whole face. I have 
often seen a small child being held or tended by another not much bigger, 
raise its hand to brush away the mass of flies on its face and be prevented 



452 SANITARY ENTOMOLOGY 

from doing it. They are from the earliest childhood accustomed to the 
presence of these insects, and after being prevented from disturbing them 
during the early months of life they do not seem to mind them. 

As a result of this condition of things, eye diseases are very prev- 
alent in Egypt. I should not think there could be any place in the 
world where bad eyes are so often seen as in Egypt. The natives are often 
short-sighted. For instance, very few of them can read their newspapers 
without bringing them up to two or three inches of their eyes and then it 
is obvious that only one eye is used in reading. It is a curious sight to 
see these people reading in the trains and other public places. 

This condition is probably the result of some form of ophthalmia and 
is quite different from the one-eyed condition so often seen in Egypt in 
consequence of wilful mutilation of an eye for the purpose of evading 
military conscription or the payment of the small sum required to pur- 
chase exemption. 

THE SULTAN'S FUNERAL 

On the day of the funeral of the late Sultan, His Highness, Hussein 
Kamil Pasha, in October, 1917, a party of us gained admission to a 
balcony overlooking the street in the business part of Cairo. When we 
arrived, there were a number of people already there. They seemed to 
be Italians or perhaps Syrians, we couldn't tell. They spoke French. 

Among them were a number of children, six or seven in number, 
the eldest being about 16 or 17 years and the youngest some 7 or 8 years 
of age. After a time I noticed in the hair of the eldest, a girl of the bru- 
nette type with very dark hair, a whitish streak across the side of the 
head from near the forehead well back to where the hair was gathered into 
the long braid which hung down her back. This white streak must have 
been about an inch and a half to two inches in width and some five or six 
inches long. I saw that the whitish appearance was due to the presence of 
masses of nits of the head louse. I then noticed the heads of the other 
children there and found that they were all the same. Every head was 
full of nits. 

I actually saw the lice crawling about in the hair of these children, 
and though I watched them pretty constantly for about two hours, 
except for a few minutes when some parts of the funeral procession were 
passing, I did not once see anyone of them attempt to scratch or in any 
way take notice of the irritation which must have been caused by the lice. 

The general appearance of these children was one of a fair degree 
of neatness and cleanliness, and yet they were so inured to the attacks 
of these parasites that they paid not the slightest attention to them. 
I have never seen anywhere such a heavy infestation of these vermin. 



CHAPTER XXXIII 

Insects in Relation to Packing Houses * 
E. W. Laake 

Before the meat packing establishments of the United States were 
placed under government inspection, there was very little attention paid 
to insects and their control in such establishments, unless there was 
a direct loss to the packer, and even then only such methods as were 
necessary to meet the immediate situation, rather than the requirements 
of permanent sanitation, were employed. During the first years follow- 
ing the institution of inspection by the Bureau of Animal Industry under 
the law of 1906, packing plants were remodeled or rebuilt according to 
government specifications, and conditions were vastly improved from a 
sanitary standpoint, although the insect question was not handled vigor- 
ously until during the past few years. The importance of safeguarding 
from contamination and infection the millions of tons of meat and meat 
products prepared by the numerous packing houses in the United States 
is indeed a task worthy of attention, especially during the present time 
when our products are so direly needed at home and abroad. That insects 
play as great a role by contamination or actual destruction of meats 
and meat products as they do in other branches of agricultural industries, 
is easily demonstrated when one becomes familiar with the ravages of 
these pests in the numerous establishments in our country. 

Flies are the principal cause of annoyance and loss around packing 
houses. The house fly is probably of first importance. It is especially 
troublesome around the loading docks, in sausage kitchens and in markets. 
The blow flies are often very abundant, especially in departments handling 
inedible materials. In this country the black blow fly, Phormia regina 
Meigen, is probably the most important. The green bottle flies, Lucilia 
sericata Meigen and L. caesar (Linnaeus), rank second, and in the south- 
ern half of the United States the screw worm fly, Chrysomya macellaria 
(Fabricius), is the predominant species in the summer months. Others 
concerned are the bluebottle flies, Calliphora spp. and Cynomyia cada- 
verina Robineau-Desvoidy ; flesh flies, Sarcophaga spp. ; Muscina stabulans 
Macquart, M. assimilis Fallen, Ophyra spp., Chrysomyza spp., and the 

1 This lecture was read July 29, and issued August 8, 1918, and is now reproduced 
practically in its original form. 

453 



454 SANITARY ENTOMOLOGY 

skipper fly Piophila casei Linnaeus. Hide and ham beetles, mostly of the 
family Dermestidae, are of local importance, especially as destructive to 
hides. The three common cockroaches are to be found, especially the 
American roach and the Croton bug. 

Associated with all the larger packing houses are large stock yards, 
horse and mule barns, rendering plants, and thickly populated districts, 
all of which are prolific insect breeding places. These furnish part of 
their millions of flies, with those produced on the premises of the packing 
plants themselves, to constantly attack the fresh products of the estab- 
lishments. Sanitation throughout the establishments and premises under 
government inspection, and in railway cars and other vehicles used in 
transporting meats, is rigidly enforced, but government inspectors have 
no jurisdiction over sanitary matters beyond that, no matter how bad 
the existing conditions may be. 

With efficient city health departments a great deal can be done cooper- 
atively with the sanitary force of the packing establishments, but this is 
not always possible and as a result the production of myriads of flies 
goes on constantly in the immediate neighborhood of the plants and the 
task of protecting meat products and controlling flies at packing houses 
becomes proportionately more perplexing. In our Southern States this 
is an all-year-round work, due to the fact that our winters are rarely 
sufficiently severe to cause the death of immature stages and during warm 
days numerous adults emerge and seek food and protection in the con- 
stantly heated tankage and blood-drying rooms or other favorable 
departments. Here they also find large stores of excellent breeding 
material and can develop to maturity in a comparatively short time during 
the winter months. The breeding of blow flies in large accumulations of 
tankage and blood in drying rooms, as it is found in many packing houses, 
may take place during the winter even in the more northern latitudes 
as there are many species of blow flies that are quite resistant to cold 
and have the advantage of many warm, protected places during severe 
winter. 

That flies are carriers of many different diseases is well known. The 
germ-laden flies can easily contaminate many different cured meat 
products which are sometimes consumed without being cooked, or con- 
taminate fresh meat products with putrefactive, non-pathogenic and path- 
ogenic bacteria, in this way hastening decomposition, and rendering the 
meat unfit for food. There is also loss of much meat that is "blown" 
with eggs or damaged by skipper fly larvae. 

Next in importance to flies in meat packing establishments are cock- 
roaches. Although they are not as numerous as flies, they are present 
in almost all establishments just as they are more or less plentiful in 
dwelling houses. The damage done by cockroaches is due not so much 



INSECTS IN RELATION TO PACKING HOUSES 455 

to what they actually consume, which is necessarily a small amount, but 
to losses of portions of food which are contaminated and rendered 
nauseous. The presence of roaches leaves a fetid odor which is persistent 
and foods so tainted are almost beyond redemption. This odor comes 
chiefly from a dark-colored fluid excreted through the mouth of the insect 
and perhaps also from the scent glands occurring between certain seg- 
ments on the bodies of both sexes, from which an oily liquid of a disagree- 
able odor is secreted. Favorable conditions for the existence of cock- 
roaches are found within all packing houses, namely, abundant food sup- 
plies of all kinds, good protection in the winter, and many good breeding 
places. 

Skipper larvae and hide beetles are often found by the millions in the 
bone storage houses, especially in stores of bones collected at large in the 
country, where pieces of dried muscular tissue and skin are attached. 
These insects are not so often found in the department of edible supplies 
of the packing plants, as the packers are well aware of the damage done 
by them, especially in cured and dried products, and a constant watch is 
kept to prevent their appearance or to quickly exterminate them when 
they do appear in such departments. 

INSECT-BREEDING PEACES AND THEIR TREATMENT 

The importance of proper construction and arrangement of abattoirs 
and packing plants with a view to eliminating insect breeding places and 
protecting the food products from insect contamination can not be over- 
estimated. In plants already in operation many bad fly-breeding places 
can be permanently eliminated by construction work. For instance much 
future trouble can be avoided by constructing concrete catch basins, pav- 
ing docks, loading tracks, and stock pens, providing adequate driers for 
bones, fertilizers, etc., and ample dry storage facilities for inedible 
products. Excellent breeding media of both vegetable and animal matter 
are almost constantly present and are often found in huge quantities 
in various places on the premises of establishments or on "dumps" near 
the plants. Too often these large accumulations are neglected for some 
cause or other, and insects, especially flies, have ample time to develop 
and emerge by the millions, and many such places, especially those not 
under government supervision, are constant producers of myriads of 
flies throughout the warmer seasons of the year. 

The undigested food of cattle, called paunch manure, and the con- 
tents of hog stomachs, together with the horse manure and stable clean- 
ings from the horse barns, partly blood-saturated sawdust from the meat 
coolers and sediment from catch basins saturated with bloody water, are 
usually hauled to a general dumping ground. These dumps are thus 



456 SANITARY ENTOMOLOGY 

rendered very attractive to house and blow flies and nearly all of this 
material is wet when it is dumped and must have a day or two of hot 
weather in order to dry sufficiently to burn well. If it remains as long as 
four days before burning, which is often the case during rainy weather, 
fly larvae have sufficient time to develop before the material becomes dry 
enough to be burned, and migrate to a nearby place where they enter 
the ground and complete their life cycle. 

For the destruction of paunch manure, etc., incinerators of various 
types are used by some packing plants and stock yards. At Omaha, 
Nebraska, the Stock Yards Company has erected a huge incinerator of 
a special type that contains sixteen large cells equipped with water pipes 
throughout. As the contents of some of the cells are slowly burning, the 
water pipes are heated and the hot circulating water dries the contents 
of the freshly filled cells which are later also slowly burned. The ashes 
and charred material are then removed, mixed with finely ground, dry, 
sheep manure and sold for fertilizer. At least six men are constantly 
employed filling the cells and removing the charred contents and the 
returns realized from the fertilizer are said to be sufficient to pay for all 
labor and pay a reasonable amount of dividends on the investment of the 
incinerator plant, which was erected at a cost of $40,000. 

Other types of incinerators in use, which are operated mostly by pack- 
ing plants for the disposal of paunch manure and refuse of all kinds, are 
single and double cell brick structures where everything is completely con- 
sumed and the ashes are used for fillers of various fertilizers. At Chicago 
one plant hauls all its paunch manure and refuse on railroad cars a short 
distance away to an incinerator made of a series of old discarded iron 
rails which slope from the top of the track embankment to the ground, 
leaving a considerable air space below. Here a fire is constantly kept 
burning and consuming the manure and waste piled on the rails above. 
Ashes filling the space below the rails are removed when necessary and are 
mixed with other fertilizers. At a few large plants the paunch manure is 
loaded daily on railroad cars and is shipped out two or three times a 
week to places in the country where the manure is sold to truck farmers. 
The trackage beneath the cars along the loading docks is paved with 
concrete to prevent full grown larvae from escaping from the loaded cars 
when they are held over several days. The paving extends well around 
and beyond the length of the cars and near the outer edge it is provided 
with a narrow, deep gutter filled to half its depth with water where it is 
connected with the sewer. This arrangement carries off the excess 
water and traps the maggots as they endeavor to migrate to a place for 
pupation. 

When treatment of infested dumps is necessary, borax solution or 
crude oil is mostly used. Spent fuller's earth, a waste product from oil 



INSECTS IN RELATION TO PACKING HOUSES 457 

and lard refineries at packing houses, is also used at some plants with 
fairly good results, if the earth is thoroughly mixed with the paunch 
manure and waste, or is used as a covering. Spent fuller's earth, when 
it is discarded at the refineries, contains about 8 per cent of oil and acts 
as a larvicide besides being a repellent for several days. In experiments 
at a Dallas packing house a saturated solution of arsenic was also found 
to be very effective for killing larvae in paunch manure. 

Many other breeding places of importance exist around the plants, 
such as the hog hair, tankage, blood cooking, and drying rooms ; in ferti- 
lizer buildings ; along fertilizer loading docks where pulverized tankage 
and blood and bone meal accumulate on the ground under the docks ; and 
along car tracks where the soil becomes moistened by rain or by open 
sewage disposal lines, quite often found under such docks. Often the soil 
so covered with moist animal matter is found to be heavily infested with 
blow fly larvae. Borax treatment for such infestations is very effective but 
must be repeated frequently as fresh material is always accumulating and 
is readily reinfested. Crude oil or fuller's earth applied heavily on such 
breeding places packs the soil down well and also renders it less attrac- 
tive for flies for a much longer period. It has repeatedly been observed by 
the writer that where enough oil or fuller's earth had been applied there 
was no fly breeding going on. When the capacity of a packing plant is 
overtaxed, or when labor is short, large stores of bones and hog hair do not 
get thoroughly dried in the hot air driers and these then become heavily 
infested with blow fly and skipper fly larvae. The same condition is also 
often found in storage houses containing bones, hair, blood, and tankage 
that have been thoroughly dried, but again moistened by water leaking 
through a bad floor or bad roof above. To prevent fly breeding in any 
of this material it must be thoroughly dried and then stored in an abso- 
lutely dry place. 

Another common source of fly production found at packing plants is 
under and around stick-water vats where the glue stock is manufactured. 
Steel and wooden vats are used for boiling stick-water and sooner or 
later these vats may become leaky or are heated to such an extent that 
the stick-water boils over and saturates the soil below. Prolific fly breed- 
ing then takes places. Borax solution or crude oil treatment for sucli 
infestations is very effective. In the stock yards the hog pens are usually 
all paved and the manure is washed into sewers leading to a nearby stream. 
In many instances the sewer outlet is not directly into the water and the 
manure is deposited in large quantities along the banks of streams where it 
becomes heavily infested with fly larvae which develop in the moist manure, 
thence migrating to dry places for pupation and emergence. The manure 
mixed with hay and straw from cattle pens is usually hauled to nearby 



458 SANITARY ENTOMOLOGY 

dumping grounds and is there allowed to decompose, or is occasionally 
burned over, but very seldom incinerated. 

Cockroaches are found in the blood and tankage rooms, dressing 
rooms, and other departments that are not under refrigeration. Modern 
steel and concrete construction has much to do with eliminating these 
insects. The use of steam and hot water in cleaning up the machinery, 
walls and floors of all the departments and rooms containing edible goods 
destroys most of them that come in during the night and do not return 
to their better protected hiding places in the departments of inedibles 
where there are also good breeding places. Where steam and hot water 
cannot be used freely against roaches, the dusting of sodium fluoride is 
very effective. About four pounds of sodium fluoride, applied with a dust 
gun by the writer in a dry salt cellar and tankage drying room at a 
certain packing house, killed over 5,000 roaches and thoroughly cleaned 
away the pest. A thorough inspection of these same departments months 
later revealed only a few roaches which probably came in from other 
departments of the plant that were not treated. 

When skipper fly larvae are found in cured meats the products infested 
are trimmed and the storage rooms thoroughly cleaned, or if the infesta- 
tion is severe, the meat products are rendered for inedible purposes, the 
uninfested products removed and the storage rooms fumigated. 



PROTECTION AGAINST INSECTS 

That flies can be kept out of- packing houses to such an extent that 
they are not objectionable is well demonstrated in some of the large 
plants at Kansas City, Missouri ; Davenport, Iowa ; Omaha, Nebraska ; 
Milwaukee, Wisconsin, and Topeka, Kansas ; which are completely and 
thoroughly screened and remain remarkably free from flies on the inside 
although flies are plentiful on the outside. 

For the protection of meats against skippers it is necessary to screen 
closely with twenty-mesh wire. It is also necessary to keep the store- 
rooms darkened. The use of fly traps around packing plants is fully 
justified. Even though everything possible is done to eliminate breeding 
places on the premises, great numbers of flies come from the surrounding 
district to the attractive conditions which are to be found around packing 
establishments. Our investigations have shown that flies quickly come to 
slaughter houses when liberated at nearly a mile distant. No doubt they 
often travel much farther to such establishments. Traps of various 
models are used extensively at packing plants and where traps are well 
handled great quantities of flies are captured. Accurate records kept by 
some plants show that as high as 285 pounds of flies were captured in 



INSECTS IN RELATION TO PACKING HOUSES 459 

one week with 65 traps of the conical hoop type. This type is by far the 
most efficient all-round fly trap of some twenty different kinds tested at 
packing plants. 

The most attractive bait for blow flies is the mucous membrane which 
is freed from intestines after it has become sour. At packing plants this 
material is known as "gut slime" and when it becomes warm it ferments 
rapidly, giving off a very obnoxious odor that is especially attractive to 
blow flies and also a very good bait for house flies. However, on account 
of its bad odor it cannot be used in departments of edible foods or on 
loading or shipping docks. Sugar or molasses, one part, to three parts 
of water, makes a very good bait, especially for house flies. A cheap, black 
molasses mixed with three parts of water and allowed to stand a day or 
two before it is used to bring it to fermentation is a very cheap and 
effective bait. 

Fl} 7 paper used extensively in screened rooms catches practically all 
flies that have gained entrance through doors which are necessarily opened 
and closed where much trucking is done. Screening of some doorways' 
which are constantly in use by in and outgoing trucks is not practicable as 
flies light on trucks and follow them through the doors, and soon congre- 
gate on the inside of such rooms or departments. 

To exclude flies from entrances of such doorways a rapidly revolving 
ceiling fan or rotarj 7 blade fan operated at a high rate of speed has been 
found to expel flies very effectively. When they enter the air current;, 
which should be directed down and outwardly, they are driven out 
through the entrance. 

Where breeding places are reduced to a minimum, where the plant is 
well protected by thorough screening, and where flies are effectively 
trapped, there is very little loss of meat or meat products, and the plant 
is in a sanitary condition from an entomological standpoint. 



A BIBLIOGRAPHY OF LITERATURE DEALING WITH SANITATION OF MEAT 
PACKING ESTABLISHMENTS 

Allen, R. M., and McFarlan, J. W., 1913. — The Municipal Abattoir. 

Kentucky Agr. Exp. Sta., Bui. 173. 
Anon, 1913. — The Protection of Meat from Flies. Australian Medical 

Gazette, vol. 33, No. 18, May 3. 
Bishopp, F. C, 1915. — Flies Which Cause Myiasis in Man and Animals. 

Some Aspects of the Problem. Journ. Econ. Ent., vol. 8, No. 3, 

pp. 317-329. 
Bishopp, F. C, 1916.— Flytraps and Their Operation. U. S. Dept. Agr.. 

Farmers' Bulletin 734~ 



460 SANITARY ENTOMOLOGY 

Bishopp, F. C, 1917. — Some Problems in Insect Control About Abattoirs 
and Packing Houses. Journ. Econ. Ent., vol. 10, No. 2, pp. 269- 
277. 

Bureau of Animal Industry, 1906. — Regulations Governing the Meat 
Inspection of the United States Department of Agriculture. Order 
No. 137. 

Bureau of Animal Industry, 1912. — Service Announcements, June. 

Bureau of Animal Industry, 1914. — Regulations Governing the Meat In- 
spection of the United States Department of Agriculture, Order No. 
211. 

Bureau of Animal Industry, 1915. — Service and Regulatory Announce- 
ments, March. 

Farrington, A. M., 1908. — The Need of State and Municipal Meat In- 
spection to Supplement Federal Inspection. Bureau of Animal Indus- 
try, Circular 154. 

Melvin, A. D., 1908. — The Federal Meat Inspection Service, Bureau of 
Animal Industry, Circular 125. 

Melvin, A. D., 1912. — State and Municipal Meat Inspection and Munic- 
ipal Slaughterhouses. Bureau of Animal Industry, Circular 185. 

Parks, G. H., 1911. — The Sanitary Construction and Equipment of Abat- 
toirs and Packing Houses. Bureau of Animal Industry, Circular 
173. 

Shaw, Geo. H., 1914. — The Federal Meat Inspection Service and Sanita- 
tion of Packing Houses under Its Supervision. American Journal of 
Public Health, vol. 5, No. 3, pp. 236-245. 



CHAPTER XXXIV 

Insect Poisoning and Miscellaneous Notes on the Transmission of Diseases 

by Insects 

W. D wight Pierce 

In the various lectures which have preceded this one, most of the 
large groups of disease-carrying insects have been discussed in full but 
there are a number of cases of carriage of disease by insects of other 
groups and there are many cases of insect poisoning which have not been 
covered. As a matter of fact the majority of species of insects which 
are chargeable with poisoning have not been mentioned. 

In the present course of lectures, for convenience, all arthropods have 
been considered under the popular term insects. The general public does 
not discriminate between a spider, a scorpion, a mite, a tick, and an 
insect as far as the general nomenclature is concerned. In fact the disease 
relationship in these different groups are so similar that any discussion 
of them from a sanitary standpoint should include all of the groups 
which belong to the Phylum Arthropoda. The scorpions belong to the 
order SCORPIONIDEA, the spiders to the order ARANEAE, and the 
mites and ticks to the order ACARINA, all in the class ARACHNIDA, 
characterized by eight legs. It is also well to consider the very nearly 
related class CHILOPODA, which includes the centipedes and millipedes 
with one or two pair of legs to each segment. The insects all belong to 
the INSECTA, characterized by six legs. 

SCORPION POISONING 

There is great popular fear of the sting of the scorpion. These 
creatures are found largeW in semitropical and tropical countries and 
are possessed of a tail with a sting at the tip. The effect of the poison- 
ing is more or less severe and in some cases is fatal. The method of 
stinging is to bring the tail forward over the body so that the curved 
spine on the last segment penetrates the skin and inflicts the wound. 
On either side of this curved barb is an opening from which the duct 
from the poison gland discharges the venom. Very little has been done 
on the toxicity of the poisons of the various species of scorpions. Castel- 
lani and Chalmers have summarized in a few pages the subject of scorpion 

461 



462 SANITARY ENTOMOLOGY 

venom. In the majority of cases when a person is stung by a scorpion, 
they fail to retain the specimen or to have a scientific identification made 
so that the records of actual species causing scorpion sting are very 
small, only twelve species having come to the attention of the writer. 
The purpose of the scorpion venom is not necessarily as a means of 
defense, but rather as a method by which it kills its prey, which usually 
consists of small animals. In man the symptoms depend upon the size 
and nature of the scorpion. 

The small European scorpion, Isometrus europaeus Linnaeus, causes 
only pain, redness, and local swelling. Some of the larger tropical scor- 
pions cause intense pain of a burning character radiating from the skin, 
associated often with violent convulsions, mental disturbances and hal- 
lucinations, profuse perspiration, secretion of saliva, and perhaps vomit- 
ing. The pulse is weak and quick and the respiration is hurried and 
shallow. These symptoms gradually diminish in three to eight hours 
and by about nineteen to twenty hours the person usually is normal. 
Death may ensue due to collapse or stoppage of respiration which is 
more apt to happen in children than in adults. Wilson states that the 
mortality in children under five is 60 per cent for Buthus quinquestriatus 
H. & E., a species of Upper Egypt and the Sudan. Fatal poisoning is 
also charged against Buthus maur us and other North African scorpions. 
Cararoz has stated that as many as two hundred persons die annually 
from scorpion sting in the neighborhood of Durango, Mexico. The species 
which is responsible for this is Centrurus eoclicaude Wood. In addition 
to the species already mentioned, Buthus martensi Karshi of Manchuria ; 
Buthus occitanus Amour of South Europe and North Africa .; Buthus afer 
Leach, Prionurus citrinus, P. amoureuni Savigny, Androctonus funestus 
Ehrenberg, and Heterometrus maurus, all of South Africa, have been 
recorded as causing severe poisoning. Kubota found the Durango scor- 
pion many times more toxic than the Manchurian. The common southern 
species in the United States, Buthus carolinianus Beauvois, which ranges 
from the Southern Atlantic States into Texas, north into Kansas, inflicts 
a very severe sting which hurts for many hours. 

Castellani and Chalmers recommend as treatment for scorpion sting 
the application of a proximal ligature and incision and treatment of the 
wound with permanganate of potash in the same manner as used for 
snake bite. C. V. Riley in 1887 recommended the use of ammonia applied 
over the sting, or a small dose of ipecacuanha. Simpson recommends 
the local application of a paste of ipecacuanha. Colonel Duke recom- 
mends that 5 to 10 minims of a 5 per cent solution of cocaine be injected 
subcutaneously, close to the sting, for adults, and 1 to 5 minims for in- 
fants and children. Murthy (1919) considers that larger quantities of 
a weak solution of cocaine hydrochloride are better than smaller quantities 



INSECT POISONING AND MISCELLANEOUS NOTES 463 

of stronger solution. He has used successfully a dosage of 20 to 30 
minims of a solution of 20 grains cocaine to the ounce, injected exactly 
on the sting. A number of different writers have prepared anti- 
venoms or serums which are capable of neutralizing the venom. Villala 
reports the preparation of an antiserum in Brazil which was successfully 
used in the case of a child affected with a very severe scorpion poison- 
ing. 

SPIDER POISONING 

There is more or less general fear among the public, due to many 
legends which have been passed down, as to the severity of spider poison- 
ing. The majority of spiders are not poisonous but there are certain 
species which are extremely poisonous. The spiders most feared in 
America are the tarantulas, large hairy spiders. The tarantulas, like 
other spiders, have poison jaws for killing or paralyzing their prey. 
There are very few scientific records of tarantula poisoning in America. 
Vorhies has cited four without mentioning the species. The American 
tarantula which has been regarded as poisonous is Phidippus audaoc 
Hentz. In Europe, tarantula poisoning is caused by Lycosa tarantula 
Linnaeus, L. narbonensis Walckenaer, Epeira diadema (Moritz-Herold) 
Walckenaer, and Trochosa singoriensis (Laxmann). Epeira diadema is 
the common garden spider of Europe and is not as large as the American 
tarantula. The bite of Lycosa tarantula produces wheals surrounded by 
red areola but no general symptoms result. 

The evidence against the hour-glass spider, Latrodectes mactans 
Fabricius, and its allies is far more convincing and there is no doubt 
that these are dangerous spiders. This species is coal black and marked 
with red or yellow or both. It is quite variable in markings. The 
full grown female is about a half-inch in length and its globose abdomen 
is usually marked with one or more red spots on the dorsal line. This 
spider occurs in old buildings, stables and wood piles. It spins an irregu- 
lar web which is composed of very coarse, silk threads. It is an exceed- 
ingly aggressive spider. Severe and sometimes fatal poisoning follows 
the bite. Kolbert has isolated a substance from the poison gland 
(Arachnolysin) which is a powerful hemolysin. Dr. E. H. Coleman, Los 
Altos, California, has conducted quite a series of experiments with 
Arachnolysin and with a toxalbumen which occurs throughout the body of 
the insect. He dissected the poison glands and made various triturations 
from which he prepared powders which he took himself and noted the 
effects upon himself after each dose. After taking twenty-five powders, 
his heart rate was reduced to 48 and his temperature was 99. He expe- 
rienced a severe headache, clonic spasms of the thoracic and abdominal 
muscles, marked distress about the heart with radiating pains extending 



464 SANITARY ENTOMOLOGY 

to the left arm pit and down to the elbow. He had no bowel action for 
two days and the pupils were markedly dilated. His symptoms appeared 
to him a perfect picture of angina pectoris. The symptoms subsided and 
in three days he felt normal. He repeated this experiment twice with the 
same results. 

Doctor Coleman had a patient aged 54 years suffering from angina 
pectoris. During an attack he gave him a powder of one of the tritura- 
tions of the spider venom and in ten minutes the symptoms passed leav- 
ing the patient more comfortable than after any previous attack. 

At least one case of death is recorded from the bite of this species and 
several cases of severe poisoning have come to the attention of the 
Bureau of Entomology. 

Houssay gives quite a description of the symptoms and literature. 
He counsels the use of morphine, bromide, or camphor oil. He cites 
also the use of chloral and as cardiac tonics, caffein, and acetate of 
ammonia, aiding any of these by milk diet and theobromine. 

Doctor Coleman records treating a case by hypodermic injections of 
strychnine 1/40, followed in ten minutes by nitroglycerine 1/100, and 
local applications to the site of bite of crystals of potassium perman- 
ganate. By repeated injections of strychnine the heart rate was increased 
to 45. He then substituted the use of brandy hypodermically. Heat 
was applied to the feet and back. Nine and one-half hours after the 
attack the heart rate had been increased to 55 and the pains were still 
severe. A % morphine with 1/150 atropine was given. The pains eased 
up and the patient dropped asleep. The next day he was covered with a 
fine rash. The heart rate was 60. This rash disappeared in four days. 
He suffered from insomnia for several days and a stubborn constipation 
that took a very active purge to affect. After three years his heart rate 
was 64, he was troubled with insomnia, and a marked bulimia. 

Fatal spider poisoning has been recorded as caused by Latrodectes 
geometricus Koch in California, L. hasseltii Thorell (scelio Thorell) (the 
"katipo") in New Zealand, Theraphosa javanensis Walckenaer in Java, 
Chirac anthum nutrix Walckenaer in Europe. Theridium 13-guttatum 
Fabricius in France and Italy, and T. lugubre Koch ("kara kist") in 
Russia. 

CENTIPEDE POISONING 

The centipedes, on account of their large size and many sharp legs, 
have given rise to numerous popular legends as to their poisonous nature. 
It is a common saying that when a centipede grips hold of a person, the 
impression made by each claw gives rise to a sloughing of the flesh. This 
opinion is quite erroneous as the centipede has only one pair of poison 
glands, located in the head, having their external opening through a pair 



INSECT POISONING AND MISCELLANEOUS NOTES 465 

of venom claws which are large-clawed appendages lying beneath the 
head. The opening of the venom duct in Ethmostigmus spinosus, which 
has been carefully studied by Cornwall, is on the dorsal surface of the 
claw a little way from the apex and somewhat near the external side. 
There is one venom gland in each of two venom claws. This species is 
nocturnal in habit and is not naturally vicious and will not bite unless 
hurt or worried. A centipede's bite may be merely a snap, but once he finds 
his fangs sink into the fine tissues his main idea, if other portions of him 
are not being mistreated, seems to be to eat. To this end he digs as many 
legs as he can apply into the subject, the posterior ones to obtain a firm 
hold, and the anterior ones to knead the tissues. The venom claws are 
worked in and out and with the help of the first pair of legs the skin of 
the subject is pushed into the mouth. In five minutes a centipede will 
thus consume a length of rabbit skin nearly one centimeter long. The 
main function of the venom claws is to hold the food tightly against the 
mouth-parts to facilitate mastication. The slow but regularly continued 




Fig. 88. — A centipede, Scolopendra morsitans (Bradford). 

relaxation and closing of the venom claws is designed to permit the flow 
of venom into that part of the food which is to be taken into the 
mouth. The toxic action is so slow that the venom would be practically 
useless for destruction or defense. Cornwall believes therefore that the 
venom principally serves as a digestive juice. 

Other species of centipedes which have been recorded as venomous are 
Scolopendra cingulata Latreille, S. gigantea Linnaeus, S. morsitans Lin- 
naeus (fig. 88), S. her os Girard, and Geophilus similis Leach. 

The centipede bite may cause some local pain, swelling, and erythema 
lasting a few hours. The general symptoms are great mental anxiety, 
vomiting, irregular pulse, dizziness, and headache. When severe local 
inflammation follows a centipede bite, it is chiefly due to septic infection. 
A large centipede which has secured a firm hold of the skin by digging in 
its fangs and legs can almost be torn in half before it can be induced to let 
go, and in delicate skins each leg can, under such circumstances, make a 
punctured wound which will admit infective organisms. The use of dis- 
infectants to prevent infection by outside organisms is therefore neces- 
sary. 

Vorhies has described two cases of Arizona centipede bite, in both 
of which the pain was severe and prevented sleep. 



466 SANITARY ENTOMOLOGY 

Castellani and Chalmers recommended for centipede bites the bathing 
oi the parts with a solution of ammonia (1 in 5, or 1 in 10). After bath- 
ing apply a dressing of the same alkali, or if there is much swelling and 
redness, an ice bag. If necessary give hypodermic injections of morphia 
to relieve the pain. 



CENTIPEDES IN NASAL CAVITIES AND ALIMENTARY CANAL 

There are in literature quite a number of references to the occur- 
rence of small centipedes in the nasal cavities and in the alimentary canal. 
In the nasal cavities they have been charged with causing considerable 
inflammation and in the alimentary canal have caused pain, cramps, and 
nausea. Very little is known of the cause of this attack but presumably 
it is more or less accidental, probably when the person is asleep out of 
doors. The following species have been recorded from the nasal cavities : 
Geophilus carpophagus Leach, G. electricus Linnaeus, G. cephalicus 
Wood, G. similis Leach, Lithobius forficatus Linnaeus, L. melanops New- 
port, Scutigera coleoptrata Linnaeus, Chaetechelyne vesuviana Newport, 
Polydesmus complanatus Latreille, lulus terrestris Linnaeus, /. londinen- 
sis Leach, Himantarium gervaisi, Stigmatogaster subterraneus (Leach). 
There is no evidence that these parasites cause any inflammation by their 
venom. They are generally expelled from the nose in attacks of sneez- 
ing or spontaneously. The best method of making them leave the nos- 
trils is the use of snuff, Eau de cologne, or turpentine, but in some 
instances surgical operations are necessary. 

This subject has been more fully treated by Blanchard in vols. 1 to 
6 and 14 of the Archives de Parasitologic 

LEPIDOPTEROUS LARVyE POISONING 

It is not uncommon for persons to be more or less badly poisoned by 
the barbed hairs of lepidopterous larvae. In some cases these hairs contain 
minute drops of poison. The most famous poisoning of this kind is known 
as "BROWNTAIL RASH" which, when it attacks the eyes, is called 
OPHTHALMIA NODOSA. This is caused by the browntail moth 
Euproctis chrysorrhoea Linnaeus. There have been numerous cases of 
browntail rash in New England. The stinging hairs sometimes pene- 
trate into the lungs, as well as entering the eyes. This is most likely to 
happen at the time the caterpillars are molting and the air is filled 
with hairs. Entomologists working in laboratories where this species is 
being studied have suffered considerably from this poisoning. The larva is 
provided with four rows of setigerous tubercles which bear barbed hairs, 
larger at the apex than at the base. These hairs are connected with 



INSECT POISONING AND MISCELLANEOUS NOTES 467 

poison glands, one of which lies beneath each papilla or tubercle. The 
poison is liberated in the blood through the sharp basal point of the 
hairs when they come in contact with the human skin. One case of death 
has been reported. The structure of the poison glands and hairs is 
discussed by Miss Kephart. 

Ellingham has described poison hairs on the larva of Porthesia similis 
Fuessly, the swan moth. 

The processionary caterpillar Cnethocampa pityocampa Borowaki, 
according to Beille, is provided with poison-secreting, setigerous 
tubercles which are divided into four areas by two bands, which cross 
the tubercles at right angles to each other and which are free from 
hairs. The four sectors thus made are covered with chitinous papilla 
which bear poison hairs and which are connected with the subjacent parts 
by pore canals in the cuticle. The glandular part exists only under 
the sectors covered with hairs. These glands are unicellular and in the 
form of very elongate pears. These poisonous hairs, when they come 
in contact with the flesh, cause an urtication. 

In a similar manner the larva of the nun moth, Lymantria monacha 
(Linnaeus); the gipsy moth, Porthetria dispar (Linnaeus), the Io moth 
Automeris io (Fabricius), Hemileuca maia Drury, Lasiocampa pint (Lin- 
naeus), Macrotliylacia rubi (Linnaeus), Sibine stimulea Clemens, are pro- 
vided with poisonous hairs. Lagoa crispata Packard and Megalopyge 
opercularis (Smith and Abbott) are known as flannel moths, and are 
covered with long, silky hairs and do not look like caterpillars. Inter- 
spersed among the long hairs are numerous short spines connected with 
the underlying poison glands. These hairs are capable of producing a 
marked nettling effect when they come in contact with the skin. 

Riley and Johannsen present a very interesting discussion of net- 
tling insects and suggest for treatment the application of weak solutions 
of ammonia or a paste of ordinary baking soda. In the browntail dis- 
trict, one remedy which is commonly used was recommended by Kirk- 
land: 

Carbolic acid % gram 

Zinc oxide . % oz. 

Lime water . . . 8 oz. 

BEE, WASP, AND ANT STINGS 

Many species of bees, wasps, and ants are capable of inflicting painful 
stings. These insects sting by means of the ovipositor. Only the female 
is capable of inflicting injury. All persons who have handled bees are 
familiar with the sting of the honey bee, Apis mellifera Linnaeus, and 
most boys are familiar with bumble bee (Bombus spp.) stings. 



468 SANITARY ENTOMOLOGY 

The wasps most likely to sting are species of Vespa and Polistes. 

The most aggressive stinging insects in America are the Texas 
Agricultural ants of the genus Pogonomyrmex, especially P. barbatus 
Smith and P. calif ornicus Buckley. These ants will attack any one who 
comes in the vicinity of their large nests or who stands in their path. 
The immediate effect of their sting is a paralysis of the limb affected. 
The pain is very severe, and it is recorded that the sting of these ants 
is fatal to young pigs. 

HONEY POISONING 

In South and Central America one very frequently sees the stingless 
honey bees of the genera Melipona and Trigona at meat. The honey of 
these bees is eagerly collected by the natives for food. According to 
Wheeler and Von Ihering there are numerous cases of poisoning from 
eating this honey. This poisoning is manifested by intestinal disorders, 
sometimes causing paralysis and vomiting, while the honey of other species 
causes eczema and skin diseases and death has been recorded. 

Wheeler states that Trigona bipunctata Lepeletier, T. amalthea 
(Olivier) Jurine, and T. ruficrus (Latreille) Jurine make the wax of 
moist earth collected along streams and drains or from the feces of ani- 
mals and man. He noted T. ruficrus at Gatun, Canal Zone, visiting gar- 
bage barrels in great numbers in company with house flies and blow flies. 
He has observed T. bipunctata at Guatemala collecting human excrement 
in open latrines and along railway tracks, and T. pallida Latreille was 
noted at Gatun collecting crude black oil used as a mosquito larvicide. 

According to Von Ihering the honey of T. limao Smith is frequently if 
not always poisonous, causing vomiting, convulsions, pains, and weaken- 
ing of the joints. He cites several cases. Von Martius claims that there 
is a bee whose honey causes tetanus. He may have referred to this or 
related species. The cerumen or wax of this bee is sometimes so liquid 
that it mixes with the honey. 

It is easy to see that there are abundant opportunities for contamina- 
tion of the honey of this group of bees. In fact it is not uncommon to 
see our own honey bee at excrement and there is a possibility that at 
times it may contaminate its honey. 

Dr. Kebler has recorded cases of poisoning in New Jersey from eating 
honey. Honey may also be poisoned by nectar gathered from poisonous 
plants, of which Morley lists several. 

ANAPHYLAXIS 

Hadwen and Bruce have contributed to medical entomology another 
type of disease caused by insects in showing that bot larva? when crushed 



INSECT POISONING AND MISCELLANEOUS NOTES 469 

may cause anaphylaxis in an animal. Anaphylaxis essentially consists 
in the development under certain circumstances in an animal of a hyper- 
sensitiveness to foreign albuminous materials which in themselves are not 
essentially toxic. The larvae of the bots Hypoderma bovis DeGeer, H. 
lineata DeVillers, and Oestrus ovis Linnaeus are not normally toxic al- 
though by living in an animal they produce a sensitiveness. When 
crushed in the animal or when the protein material contained in the 
larvae is injected into the jugular vein of a sensitive animal, anaphylactic 
shock results. Both in natural and experimental anaphylaxis death may 
result. Recovery from the reaction gives immunity for varying periods. 



POISONING FROM EATING INSECTS 

Cornelius (1919) reports an instance of eleven cases of acute native 
poisoning in India following a feast on cooked garden bugs, Aspongopus 
nepalensis Westwood, which were collected from under stones. Recovery 
takes place in from three to ten days. Continued consumption is said by 
the natives to immunize against poisonous effects. The bug gives off an 
odor resembling sulphuretted hydrogen, but when cooked is regarded as a 
delicacy. 

KISSING BUGS 

Various species of reduviid bugs have been charged with inflicting 
severe injury with their bite. The species of Triatoma have been dis- 
cussed in Chapter 28. The black kissing bug, Melanolestes picipes in- 
flicts a very painful bite. Probably foreign matter is often introduced by 
the bite. 

DERMATITIS CAUSED BY BEETLES 

A number of species of beetles have been recorded as excreting an 
irritant liquid which causes a dermatitis to the skin which they touch. 
As an example we may cite Paederus columbirms Lap. of Brazil, which 
causes an acute dermatitis, a species of Staphylinid of the Belgian Congo 
which causes a vesicular dermatitis, and the Meloid beetles, Cantharis 
flavicornis Dufour and C. vestitus Dufour. The substance secreted by 
Cantharis is sometimes used as a cauterizing agent. 



BEETLES AS CARRIERS OF DISEASE GERMS 

We are not apt to think of beetles as carriers of disease, but there are 
a number of ways in which beetles may readily be concerned in disease 
transmission. There are quite a number of species of beetles which 
breed in carcasses and which can readily carry disease germs from one 



470 SANITARY ENTOMOLOGY 

carcass to another, thus enabling the flies and other insects which visit 
food to further distribute the germs. Proust found quantities of living 
Dermestes vidpinus Fabricius in goat skins taken from anthracic ani- 
mals. He found virulent anthrax bacillus in their excrement and also 
in their eggs and in the larvae. Heim also had occasion to examine some 
skins which were suspected of having caused anthrax in persons engaged 
in handling leather. He found the larvae of Attagerms pellio Linnaeus, 
Anthrenus museorum Linnaeus, and Ptinus also fully developed insects 
of the latter species on the skins. All these insects had virulent anthrax 
bacillus (spores) on their bodies and in their excreta. 

The greater proportion of the cases of beetle transmission of disease 
are those in which the beetle serves as an intermediate host of a parasitic 
worm. In most of these cases the beetle larvae are found in excreta. They 
ingest the eggs of the worms and the transformation takes place within 
their bodies. The worms are then eaten by animals and the infection is 
carried on. Since Doctor Ransom, in his lecture, has summarized all of 
the evidence, it is unnecessary to repeat at this time. 

We are not apt to associate the transmission of plant diseases by 
insects but the cases are strongly analogous. Just recently F. B, Rand 
has demonstrated the transmission of cucurbit wilt, which is caused by 
Bacillus tracheiphilus, by means of the cucumber beetle, Diabrotica vit- 
tata Fabr. He has found that the beetles take up the bacillus in eating 
an injured leaf and has been able to demonstrate the presence of the 
bacillus in the body of the insect by dissectiori and culture with subse- 
quent inoculation. He has conclusively proven that the disease can be 
transmitted only by means of this and closely related beetles. He has 
found also that the normal bacillus content of the abdomen may, in a 
large proportion of cases, destroy the wilt bacillus. It is quite probable 
that infection in this case is similar to that caused by the house fly, in 
that the infected excreta come in contact with the recently eaten surfaces 
of the leaf as the beetle moves forward. 

It has been found that beetles can transmit mosaic disease of tobacco. 
It is not at all out of the way to expect that we will find ultimately a 
similar transmission in this case and in many other plant diseases. 

LIST OF REFERENCES 

Castellani, A., and Chalmers, A. J., 1913. — Manual of Tropical Medi- 
cine. 

Cornelius, H. B., 1919.— Indian Med. Gaz., vol. 54, No. 2, pp. 72, 73. 

Cornwall, J. W., 1916. — Indian Journ. Med. Research, vol. 3, pp. 52- 
57, and 540-557. 

Ellingham, E. H., 1914.— Tr. Ent. Soc. Lond., 1913, pt. 3, p. 423. 



INSECT POISONING AND MISCELLANEOUS NOTES 471 

Heim, F., 1894.— -Compt. Rend. Soc. Biol., Paris, pp. 58-61. 

Kephart, Cornelia F., 1914. — Journ. Parasit., vol. 1, No. 2, pp. 95- 

102. 
Morley, M. W., 1915.— The Honey Makers. A. C. McClurg & Co., 

Chicago, pp. 188-194. 
Murthy, S. S., 1919.— Indian Med. Gaz., vol. 54, No. 2, p. 73. 
Proust, A., 1894.— Bull. L'Acad. Med., vol. 34, pp. 57-66. 
Riley, C. V., 1887.— Hand Book of Medical Science, vol. 5, pp. 741- 

760. 
Villela, E., 1917.— Brazil Med. Journ., vol. 31, No. 43. 
Von Ihering, H., 1904. — Revista Mus. Paulista, p. 11. 
Vorhies, C. T., 1917. — Poisonous Animals of the Desert. Arizona Agr. 

Exp. Sta., Bull. 83, pp. 373-392. 
Wheeler, W. M., 1914. — Journ. Trop. Diseases and Prevent. Med., vol. 2, 

pp. 166-167. 



472 SANITARY ENTOMOLOGY 



SUMMARY 

Throughout this course of lectures my main object has been to show 
the diverse manner in which insects may cause pathological conditions or 
may transmit pathogenic organisms. Unquestionably the majority of 
species which carry disease organisms have not yet been recorded in this 
role. In the past we have attempted to minimize the possible role of the 
insect as a carrier of disease. In the future it would be wise to take the 
stand that insect transmission of a disease should be one of the first 
methods of transmission investigated and that the investigation should 
be carried out on logical lines suggested by the habits of the insects 
concerned. It is to be regretted that a large part of the study of insect 
transmission of disease has been aimed at proving or denying transmis- 
sion by means of the bite of the insect. We have seen from the evidence 
presented that a large proportion of the cases of insect transmission are 
not by the bite but rather through the feces of the insect. We may 
therefore consider that many of the conclusions that insects are not in- 
volved in the transmission of certain diseases are unwarranted and that 
the cases should be reopened and studied more scientifically. 

Any insect which visits excreta or which visits food or the person of 
man or animals is to be considered a suspicious object in a disease 
transmission inquiry. Naturally we will look to the blood-suckers as 
the first means of transmitting disease of which the organism is found in 
the blood, but when the diseases are of the intestinal or genital organs, 
we are more apt to find that the disease is carried by insects which become 
contaminated by contact with infected excretions. Another unexplored 
field of study is*the determination of toxins in foods, produced by con- 
tamination of insects feeding therein. 

If through this series of lectures we have succeeded in interesting a 
few investigators to look into the subject of transmission of certain 
diseases more thoroughly, we shall feel that we have been successful in our 
efforts. 



CHAPTER XXXV 

A Tabulation of Diseases and Insect Transmission 
W. Dwight Pierce 

In view of the fact that a very large number of diseases have been 
mentioned in these lectures, and that the same disease has often been 
mentioned in several lectures, it was thought desirable to prepare a 
tabulation of the information presented in this volume in the most con- 
crete form possible. In the fourth column under method of insect trans- 
mission, I have drawn frequent conclusions as to the probable mode of 
transmission, based on analogy. In each such case a modifying word 
makes it clear that the statement is not proven. Unquestionably we must 
draw such conclusions and test them out, for by such methods we can 
greatly facilitate progress in investigation. Unquestionably in many of 
the diseases cited below, insect transmission is not the most important 
mode, but on the other hand, I am just as confident that insect trans- 
mission will prove to be the most important mode in other diseases now 
considered to be carried otherwise. In no wise in this entire course do I 
claim responsibility for proving insect transmission, nor am I able to 
justly repudiate the claims made by others. The evidence is presented 
for what it is worth and occasionally with theoretical suggestions by 
myself, but each reader must seek the original evidence and weigh it him- 
self. Undoubtedly there are many inaccuracies of fact in this tabulation 
and in the chapters on disease transmission. Some of them may have been 
corrected but overlooked in compiling the present work. 

There is always a danger that people will accept a tabulation as 
authoritative. It is not, in this case at least, a critical compilation. 



473 



474 



SANITARY ENTOMOLOGY 



Disease 



Acariasis, human and animal 
(acarine dermatosis) 



Acariasis, internal (parasitism 
of liver, kidneys, etc., pro- 
ducing peritonitis, enteritis, 
purulent urine, etc.) 



Acariasis, see also Chiggers, 
Depluming mite, Gonone, 
Inflammation (bronchial, 
lungs, catarrhal), Itch, 
Mange, Ocular acariasis, 
Otoacariasis, Paralysis 
(tick), Scabies, Scaly leg. 

Ainhum 



Amoebiasis, see Dysentery 
(amoebic) 

Anaplasmosis, African and 
Australian 



Anaplasmosis, Argentine 

Aino 

Anemia, canine 



Anemia, equine infectious 



Causative organism 



Anemia, jackal 



Anemia, jerboa (Gerbillus in- 
dicus) 



Anemia, jerboa (Jaculus gor- 
doni and J. orientalist 



Dermanyssus gallinae 

" hirundinis 

Holothyrus coccinella 
Liponyssus bacoti 
Tetranychus telarius 

Carpoglyphus alienus 
Cytoleichus banksi 
nudus 
" sarcoptoides 

Histiogaster spermaticus 
Laminosioptes cysticola 
Nephrophages sanguinarius 



Dermatophilus penetrans. 

Anaplasma marginale 

Anaplasma argentinum 
Castellanella brucei (?) 
Hsemogregarina canis 

Filterable virus 

Rossiella rossi 
Haemogregarina gerbilli 

Hsemogregarina jaculi 



Insect transmitter 



Same as preceding 
column. 



Same as preceding 
column. 



Method of insect 
transmissions 



Dermatophilus pen- 
etrans. 



Boophilus annula- 

tus decoloratus 
Rhipicephalus simus 

Boophilus annula- 
tus australis 

Glossina longipennis 



Rhipicephalus san- 
guineus 



Atylotus rufidens 
Chrysops japonicus 
Chrysozona 

pluviatilis 
Stomoxys calcitrans 
Tabanus chrysurus 

" trigeminus 

trigonus 

Hsemaphysalis lea- 
chi is possibly the 
host 

Polyplax stephensi 
is believed to be 
the host. 



Xenopsylla cheopis 
is believed to be 
the host. 



Dermanyssus gal- 
linae can carry but 
is not the usual 



Direct attack 
in skin. 



Direct attack 
in various in- 
ternal organs. 



The flea bur 
rows into the 
skin, causing 
toes and fin- 
gers to slough 
off. 

Transmitted by 
tick bite 



Transmitted by 
tick bite 

Transmitted by 
fly bite 

Taken up by 
bite of tick. 
Transmitted 
by bite of 
adult which 
was infected 
in its nymph- 
al stage. 

Thought to be 
carried b y 
bite of fly. 



Possibly trans- 
mitted by 
bite of tick 

Not definitely 
known, but 
probably 
through ex- 
creta of in- 
sect which 
takes it up 
from blood. 

Not proven but 
probably 
through ex- 
creta of in- 
sect which 
takes it up 
from blood. 

The mite may 
carry but its 
method o f 
transmission 
is not demon- 
strated. 



Nature of 
insect r61e 



Parasites 



Parasites. 



Direct attack. 



Intermediate 
host. 

Intermediate 
host. 

Intermediate 
host. 

Intermediate 
host. 



Undetermined. 



Possibly inter- 
mediate host 



Possibly inter- 
mediate host 



Possibly inter- 
mediate host 



Intermediate 
host. 



TABULATION OF DISEASES AND INSECT TRANSMISSION 475 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
insect role 


Anemia, owl (Syrnium aluco) 


Haemoproteus syrnii 


Culiseta annulata. 


Transmission 
by bite of 
mosquito. 


Intermediate 
host. 


Anemia, owl (Syrnium aluco 
and Glaucidium noctuae) 


Leucocytozoon danilewskyi 


Culex pipiens. 


Transmission 
by bite of 
mosquito. 


Intermediate 
host. 


Anemia, palm squirrel (Fu- 
nambulus pennatii) 


Heemogregarina funambuli 


Haematopinus sp. 


Transmission 
not worked 
out but prob- 
ably through 
excreta. 


Intermediate 
host. 


Anemia, rabbit (Lepus nigri- 
collis) 


Haemogregarina leporis 


Haemaphysalis flava 


Transmission 
probably me- 
chanical but 
not proven. 


Mechanical 
carriers. 


Anemia, rat 


Haemogregarina muris 


Laelaps echidninus. 


Taken up in 
blood by 
mites. Infec- 
tion by inges- 
tion of mites 
by rats. 


Intermediate 
host. 


Anemia, turtle (Testudo mau- 
ritanica) 


Heemogregarina maurit anica 


Hyalomma segyp- 
tium. 


The manner of 
transmission 
is not deter- 
mined. 


Intermediate 
host. 


Anthrax, animal and human 


Bacterium anthracis 


Chrysops coecutiens 
Haematopota pluvi- 

alis 
Lyperosia irritans 
Stomoxys calcitrans 
Tabanus atratus 
" bovinus 
" striatus 


Transmission 
by bite of fly. 


Probably me- 
chanical car- 
rier. 






Aedes sylvestris 
Psorophora sayi 


Transmission 
by bite, ex- 
perimental. 


Mechanical 
carrier. 






Calliphora 

erythrocephala 
Calliphora vomitoria 
Lucilia csesar 
Sarcophaga carnaria 


Insects swallow 
bacilli in feed- 
ing on car- 
casses or 
wounds and 
deposit in 
their feces 
on wounds. 


Mechanical 
and possibly 
biological 
carriers 






Anthrenus muse- 

orum 
Attagenus pellio 
Dermestes vulpinus 
Ptinus spp. 


Beetles ingest 
spores and ba- 
cilli in feeding 
on carcasses 
and skins. 


Mechanical 
carrier. 






Blatta orientalis 


Passes through 
intes tinal 
tract intact. 
Infection by 
contamina- 
tion. 


Mechanical 
carrier. 


Ascariasis 


Ascaris lumbricoides 


Borborus puncti- 
pennis have been 
found to carry the 
eggs. 


Larvae swallow 
the eggs. Flies 
might deposit 
the eggs on 
food. Insect 
transmission 
is not regard- 
ed as impor- 
tant. 


Mechanical 
carrier. No 
intermediate 
host is nec- 
essary. 


Babesiasis, bovine, Argentine 


Babesia argentinum 


Boophilus annulatus 
australis. 


Transmitted by 
bite of tick, 
probably in 
the same 
manner as 
cattle fever. 


Intermediate 
host. 



476 



SANITARY ENTOMOLOGY 



Disease 



Causative organism 



Insect transmitter 



Method of insect 
transmissions 



Nature of 
insect rdle 



Babesiasis, canine (malignant 
jaundice) 



Babesia canis. 



Babesiasis, canine and jackal 



Babesiasis, hedgehog 

Babesiasis. 
See also Biliary fever 
(equine), Carceag, Cattle 
fever 

Baleri 



Biliary fever, equine 



Blackheads. 



Blackheads. 
See Mange (demodectic) 

Blepharitis. 

Blepharitis. 
See Mange (demodectic) 

Browntail rash. 

See Poisoning (Lepidoptera) 

Cattle fever, Texas (Southern 
cattle fever, Splenic fever, 
Red water, Piroplasmosis, 
Mediterranean coast fever, 
Babesiasis) 



Carceag 



Chagas fever 



Babesia gibsoni. 
Babesia minense. 

Castellanella pecaudi. 

Babesia caballi. 
Bacillus necrophorus. 

Phthirus pubis 



Babesia bovis 

" bigeminum. 



Babesia ovis. 



Schizotrypanum cruzi. 



Rhipicephalus san- 
guineus. 

Heemaphysalis lea- 
chi. 

Dermacentor reti- 
culatus and pos- 
sibly 

Ixodes hexagonus 
ricinus 



Rhipicephalus simus 
is suspected. 

Dermacentor reti- 
culatus. 



Glossina longipalpis 
morsitans 
" tachinoides 
" palpalis 
and possibly 
Stomoxys calcitrans 
" nigra. 

Dermacentor reticu- 

latus 
Hyalomma segyp- 

tium are suspected 

Demodex folliculo- 
rum. 



Phthirus pubis. 



Boophilus annulatus 

australis 
Boophilus annulatus 
' annulatus 

decoloratus 
Rhipicephalus ca- 

pensis 

and possibly 
Hyalomma segyp- 

tium 

Rhipicephalus bursa. 



Triatoma megista 

" sordida 

" geniculata 

" chagasi 

Rhodnius prolixus 

Cimex lecturarius 

" boueti 

" hemipterus 

Ornithodoros mou- 
bata 

Rhipicephalus san- 
guineus 



Taken up in the 
nymphal or 
adult stage 
and trans- 
mitted by 
the bite of 
nymph o r 
adult of the 
next genera- 
tion. 

Transmitted by 
bite of tick. 

Transmitted by 
bite of tick. 



Transmitted by 
fly bite. 



Transmitted by 
bite of tick. 



The papules 
caused by 
the attack of 
the mite be- 
come infected 



Direct attack 
on eyelids. J 



Transmitted by 
bite of second 
generation. 



Transmitted by 
bite of adult 
tick which 
b e c a m e in- 
fected as lar- 
va or nymph. 

Taken up by 
the bugs from 
the blood and 
passed out in 
their feces. 

Transmission 
by inocula- 
tion of feces. 

Experimental 
transmission. 



Intermediate 
host. 



Intermediate 
host. 

Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host 



Irritation giv- 
ing entrance 
to infection. 



External para- 
site. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host 



Intermediate 
host. 



TABULATION OF DISEASES AND INSECT TRANSMISSION 477 



Disease 



Causative organism 


Insect transmitter 


Method of insect Nature of 
transmissions insect role 


Allotrombidium f uliginosum 


Same as preceding 


Direct attack 


Parasite. 


Leptus akamushi 


column. 


in skin. 




americanum 








" irritans 








Metatrombidium poriceps 








Microtrombidium pusillum 








" tlalsahuate 








Trombidium autumnalis 








batatas 








holosericeum 




% 




inopinatum 








striaticeps 








Spirillum choleras. 


Calliphora vomito- 


Taken up from 


Mechanical 




ria. 


stools by lar- 


carrier. 




Eristalis tenax. 


val and adult 






Musca domestica. 


flies, deposit- 
ed in feces or 
on food. 






Periplaneta ameri- 


May be carried 


Mechanical 




cana. 


in the roach 
body for at 
least 60 min- 
utes and de- 
posited in vi- 
able condi- 
tion in its fe- 
ces. 


carrier. 


Bacterium cholerse gallin- 


Blatta orientals. 


Passes through 


Mechanical 


arum. 




i n t e s t i nal 
tract intact. 
Infection by 
contamina- 
tion. 


carrier. 


Filterable virus. 


Musca domestica. 


Taken up by fly 


Mechanical 




Fannia canicularis. 


from animal 
manure. Was 
experimental- 
ly transmit- 
ted by con- 
tact with 
wounds and 
by inocula- 
t i o n of 
crushed flies. 


carrier. 




Stomoxys calcitrans 


Experimentally 


Mechanical 






transmitted 


carrier (?) 






by inocu- 








lation of 








crushed in- 








fected flies. 




Bacillus coli. 


Calliphora vomitoria 


Flies or larvae 


Mechanical 




Lucilia csesar 


take up from 


carrier. 




Musca domestica 


stools. De- 






Sarcophaga carnaria 


posited in 
their feces on 
food. 






Blatta orientalis. 


Passes through 


Mechanical 






: n t e s t inal 


carrier. 






tract intact. 








Infection by 








contamina- 








tion. 




Bacillus of Koch-Weeks. 


Microneurum funi- 


Insect takes up 


Mechanical 




cola. 


from eye and 
carries to eye 


carrier. 


Various bacteria. 


Pediculus humanus 


Deposited in 


Mechanical 






louse feces, 


carrier. 






carried to eye 








by hands. 




Filterable virus. 


Aedes argenteus 


Transmitted 


Intermediate 




Culex quinquefas- 


by mosquito 


host. 




ciatus. 


bite. 





Chiggers (red bugs) (acanne 
dermatosis). 
See also Gonone 



Cholera, Asiatic 



Cholera, fowl 



Cholera, hog 



Colitis 



Conjunctivitis 
Conjunctivitis, phlyctenular 



Deerfly fever 

(See plague, rodent; 



Dengue 



478 



SANITARY ENTOMOLOGY 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
insect role 


Depluming mite, chicken 


Cnemidocoptes gallinae. 


Cnemidocoptes gal- 
linae. 


Direct attack 
at base of 
feathers. 


Parasite. 


Dermatitis, beetle 


Cantharis flavicornis. 

vestitus 
Paederus columbinus 
other Meloid and 
Staphylinid beetles. 


Same as preceding 
column. 


These beetles 
secrete pow- 
erful irritant 

. liquids which 
they emit 
when attack- 
ed. 


Producers of ir- 
ritant secre- 
tions. 


Diarrhea, fowl 


Spirillum metchnikovi. 


Blatta orientalis. 


Passes through 
i n t e s t i n al 
tract intact. 
Infection by 
contamina- 
tion. 


Mechanical 
carrier. 


Diarrhea, infantile 


Bacillus of Morgan. 


Musca domestica. 


Taken up by fly 
larva ftom 
stools. Sur- 
vives through 

metamor- 
phosis. De- 


Mechanical 
carrier. Pos- 
sibly also bi- 
ological. 


Diarrhea, summer. 

See Paracolitis, Poisoning 
(food) 






posited in 
feces on food. 




Diphtheria 


Bacillus diphtberise. 


Musca domestica. 


Flies take up 
from sputum 
and deposit 
in feces on 
food. 


Mechanical 
carrier. 


Dourine 


Castellanella equiperdum. 


Stomoxys calcitrans 
Atylotus tomentosus 


Experimental 
transmission 
by interrupt- 
ed feeding. 


Mechanical 
carrier (?) 


Dysentery, amoebic 


Loschia histolytica. 


Calliphora erythro- 

cephala 
Musca domestica. 


Taken up from 
stools in en- 
cysted stage. 
Deposited in 
feces on food. 


Mechanical 
carrier. 


Dysentery, bacillary 


Bacillus dysenterise. 


Musca domestica. 


Taken up by 
larvae from 
stools. Sur- 
vives through 
metamor- 
phosis. De- 
posited in fe- 
ces on food. 


Mechanical 
carrier. 


Dy&entery, lamblian 


Giardia intestinalis. 


Musca domestica. 


Taken up from 
stools in en- 
cysted stage. 
Deposited in 
feces on food. 


Mechanical 
carrier. 


East Coast fever 
(Rhodesian fever) 


Theileria parva. 


Rhipicephalus simus 
' appendicu- 

latus 
" evertsi 
" capensis 
Hyalomma aegyp- 

tium 
Dermacentor reti- 

culatus. 
Dermacentor nitens 


Transmitted by 
the tick in 
the instar fol- 
lowing that 
in which tak- 
en up, or by 
next genera- 
tion. 


Intermediate 
host. 


Eczema 

Elephantiasis. 

See Filariasis (human) 


Pediculus corporis. 


Pediculus corporis. 


Direct attack. 


External para- 
site. 


Enteritis. 

See Acariasis. 











TABULATION OF DISEASES AND INSECT TRANSMISSION 479 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
insect role 


Erysipelas 


Streptococcus pyogenes. 


Musca domestica. 


Insect feeds on 
organism. De- 
posits in its 
feces on 


Mechanical 
carrier. 
















wounds. 




Favus (porrigo) 


Achorion schoenleini. 


Pediculus humanus. 


Manner of car- 
riage not dem- 
onstrated. 


Mechanical 
carrier. 


Fevers, tick (including tick 


Exact cause of the fever un- 


Amblyoma hebraeum 


Inoculation by 


Uncertain 


fever of Miana and inter- 


known. 


Argas persicus 


bite of tick. 


whether as 


mittent fever of Wyoming) 




Dermacentor ander- 

soni 
Hyalomma aegyp- 

tium 
Ornithodoros savig- 

nyi 




parasite or 
as carrier. 


Filariasis, canine 


Acanthocheilonema recondi- 


Ctenocephalus canis 


Possibly taken 


Possibly inter- 




tum. 


felis 
Pulex irritans. 


up by flea in 
blood. The 
method o f 
transmission 
is unknown. 


mediate host 


Filariasis, canine 


Dirofilaria immitis. 


Anopheles maculi- 


Insects take up 


Intermediate 






pennis 


in blood. 


host. 






Anopheles bifurcatus 


Worms mi- 








algeriensis 


grate from in- 








" sinensis 


sect probos- 








" superpictus 


cis to host at 








Culex penicillaris 


time of bite. 








' malaria? 










' pipiens 










" quinquefasci- 










atus 










Aedes vexans 










" argenteus. 






Filariasis, canine 


Dirofilaria repens. 


Aedes argenteus. 


Insects take up 
in blood. 
Worms mi- 
grate from in- 
sect probos- 
cis to host at 


Intermediate 
host. 
















time of bite. 




Filariasis, human 


Acanthocheilonema per- 


Partial development 


Transmission 


Intermediate 




stans. 


recorded in Man- 
sonioides africanus 
Aedes sugens 
Aedes argenteus 
Anopheles costalis 
Panoplites sp. 
Tseniorhynchus fus- 


by bite of 
mosquito, the 
exact manner 
is not de- 
scribed. 


host (?) 














copennatus 










Ornithodoros mou- 










bata. 






Filariasis, human 


Filaria bancrofti. 


Complete develop- 


Transmission 


Intermediate 


(elephantiasis) 




ment in 
Anopheles rossi 

costalis 
Culex pipiens 

" quinquefasci- 
atus 
Aedes pseudo- 

scutellaris 
Aedes argenteus 
Mansonioides afri- 
canus 
Mansonioides uni- 

formis 
Incomplete develop- 
ment in 
Anopheles sinensis 
barbirostris 
" argyrotarsis 
" albimanus 


by mosquito 
bite. 


host. 



480 



SANITARY ENTOMOLOGY 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
insect role 


Filariasis, human (cont'd) 
(elephantiasis) 




Mansonioides annu- 

lipes 
Mansonia pseudoti- 

tillans 
Culex microannula- 

tus 
Culex gelidus 

" sitiens 
Aedes perplexus 
scutellaris 
Scutomyia alboline- 

ata 
Tseniorhynchus do- 

mesticus. 






Filariasis, human 


Filaria demarquayi. 


Partial development 

is recorded in 
Aedes argenteus 
Anopheles maculi- 

pennis 
Anopheles albimanus 


Insect takes up 
in blood but 
transmission 
is not proven. 


Probably inter- 
mediate 
hosts. 


Filariasis, human 


Filaria (Loa) loa 


Culex quinquefasci- 

atus 
Chrysops centurionis 
" dimidiata 
" silacea 
Partial development 

in 
Hseniatopota cordi- 

gera 
Hippocentrum tri- 

maculatum. 


Insect takes up 
in blood. In- 
oculates a t 
time of biting. 


Intermediate 
host. 


« 








Foot and Mouth Disease 
Furunculosis, animal 


Filterable virus. 
Staphylococcus pyogenes 


Wohlfahrtia magni- 

fica 
Lucilia serenissima 

Argas reflexus 
Ixodes ricinus. 


The fly com- 
monly breeds 
in i nf ected 
feet. 

Infection at site 
of bite. 


Possibly me- 
chanical car- 
rier. 

Mechanical 
carrier. 


Gall sickness, bovine 


Trypanosoma (sens. lat). 
theileri 


Hippobosca rufipes. 


Experimentally 
transmitted 
by bite. 


Intermediate 
host. 


Gangrene 


Bacillus aerogenes capsulatus 


Musca domestica. 


Taken up from 
wounds. De- 
posited in fe- 
ces on wounds 


Mechanical 








carrier. 


Gonone (Acarine dermatosis) 


Microtrombidium wichmanni 
Schongastia vandersandei 


Microtrombidium 
wichmanni, 

Schongastia 
vandersandei 


Direct attack in 
skin. 


Parasite. 


Gonorrhea, human 

Granuloma, equine cutaneous. 
See nematode equine 


Diplococcus gonorrheal 


Fly 


Insect visited 
excreta. Car- 
ried on legs. 


Mechanical 
carrier. 


Hsemoproteasis of red grouse 
(Lagopus scoticus) 


Hsemoproteus mansoni. 


Ornithomyia lagopo- 
dis. 


Transmission 
by bite of fly. 


Intermediate 
host. 


Heartwater of sheep 


Filterable virus. 


Amblyomma hebrse- 

um 
Haemaphysalis cin- 

nabarina punctata 


Transmitted 
by bite of 
tick. 


Intermediate 
host. 


Hookworm 


Ancylostoma duodenale. 


Musca domestica. 


Insects swallow 
eggs. Deposit 
eggs on food. 


M e chanical 
carrier of no 
serious im- 
portance 


Hookworm 


Necator americanus. 


Limosiua puncti- 
pennis. 


Insecta swallow 
eggs. Deposit 
eggs on food. 


Mechanical 
carrier of no 
serious im- 
portance. 


Horse sickness, Gambian 


Duttonella congolense. 


Glossina morsitans 

and possibly 
Glossina palpalis. 


Transmission 
by fly bite. 


Intermediate 
host. 


Impetigo contagiosa 


Staphylococcus pyogenes 
(aureus and albus). 


Pediculus humanus. 


Deposited i n 
louse feces. 


Mechanical 
carrier. 



TABULATION OF DISEASES AND INSECT TRANSMISSION 481 



Disease 



Causative organism 



Insect transmitter 



Method of insect 
transmissions 



Nature of 
insect role 



Impetigo, tropical 



Inflammation, bronchial and 
lungs, in animals (internal 
acariasis) 



Inflammation, catarrhal (in 
chickens) (internal acariasis) 



Itch, bicho-colorado 
(acarine dermatosis) 

Itch, chorioptic, animal 
(acarine dermatosis) 

Itch, coolie (ground) 
(acarine dermatosis) 

Itch, copra 

(acarine dermatosis) 

Itch, grocer's 

(acarine dermatosis) 

Itch, guano 

(acarine dermatosis) 

Itch. 

See Mange (demodectic), 
Scabies 

Jaundice, infective 



Jaundice, malignant. 
See Babesiasis (canine) 

Kala azar, Indian 



Kala azar, infantile 



Kedani disease. 

See Tsutsugamushi disease 



Leprosy 



Diplococcus pemphigi con- 
tagiosa 



Halarachne americani 
attenuata 
halichaeri 

Pneumonyssus simicola 

Cytoleichus nudus 

sarcoptoides. 



Sternostomum rhinolethrum 



Tetranychus molestissimus 



Chorioptes equi 

" symbiotes. 

Rhyzoglyphus parasiticus. 



Tyroglyphus longior castel 
lanii. 

Glyciphagus prunorum. 
Tydeus molestus. 



Leptospira icterohaemorrha- 
gise. 



Leishmania donovani. 



Leishmania infantum. 



Bacillus leprae. 



Pediculus 



Same as preceding 
column. 



Sternostomum 
rhinolethrum. 



Tetranychus moles- 
tissimus. 

Same as preceding 
column. 

Rhyzoglyphus para- 
siticus. 

Tyroglyphus longior 
castellanii. 

Glyciphagus pruno- 
rum. 

Tydeus molestus. 



Pediculus corporis 
is suspected. 



Cimex hemipterus 
" lectularius. 



Ctenocephalus canis 
Pulex irritans. 



Musca domestica. 



Manner of car- 
ryingnotdem- 
o ns t r ated 
but probably 
through louse 
feces. 

Direct attack of 
mites in air 
passages pro- 
ducing as- 
phyxia. 



Direct attack of 
mites in 
throat and 
nose produc- 
ing asphyxia. 

Direct attack in 
skin. 

Direct attack in 

skin. 

Direct attack in 
skin. 

Direct attack in 
skin. 

Direct attack in 
skin. 

Direct attack in 
skin. 



Infection would 
occur through 
louse feces. 



Experimentally 
fed to bugs 
and partial 
development 
demonstrated 
but no suc- 
cessful trans- 
mission. Is 
probably 
transmitted 
through 
feces. 

The disease has 
been experi- 
mentally 
transmitted 
by fleas but 
the exact 
method is not 
proven. 



Taken up from 
lesions and 
probably de- 
posited in fly 
feces. 



Mechanical 
carrier. 



Parasite. 

Parasite. 

Parasite. 
Parasite. 
Parasite. 
Parasite 
Parasite. 
Parasite. 

Intermediate. 



[ntermediate 
host. 



Mechanical 
carrier. 



482 



SANITARY ENTOMOLOGY 



Disease 



Causative organism 



Insect transmitter 



Method of insect 
transmissions 



Nature of 
insect role 



Leprosy (cont'd) 



Pediculus humanus. 



Cimex lectularius. 



Loasis. 

See Filariasis (human) 

Leishmaniasis. 

See Kala azar, Sore (Bagdad 
Biskra, and Oriental) 

Lymphangitis, epizootic 
(animal) 



Maculae cceruleae 
Mai de caderas 



Malaria, avian 

Malaria, canary 

Malaria, pigeon 
Malaria, quartan 



Malaria, subtertian 



Cryptococcus farciminosus 
Priesz-Nocard organism 
Bacillus necrophagus 
Staphylococci. 



Phthirus pubis. 
Castellanella equinum. 

Plasmodium danilewskyi. 

Plasmodium relictum. 

Haemoproteus columbse 
Plasmodium malariae. 



Laverania falciparum. 



Amblyomma spp. 



Phthirus pubis. 



Triatdma infestans 
Cimex lectularius. 



Culex quinquefasci- 

atus 
Culex pipiens 
Aedes nemorosus 

" argenteus. 

Culex pipiens. 



Lynchia maura 
" brunea. 

Anopheles algeriensis 
' costalis 
" culicifacies 
" fuliginosus 
" funesta 
" maculipennis 
" myzomyifacies 
" quadrimacula- 

tus 
" rossii 
" sinensis 
" stephensi 
" theobaldi. 

Anopheles albimanus 
" annulipes 
" argyrotarsis 
" barbirostris 
" costalis 
" crucians 
" culicifacies 
" formosaensis II 
" fuliginosus 
" funestus 
" maculatus 



Organism has 
been found in 
bee. Trans- 
mission 
would be ef- 
f e c t e d 
through feces 

The bacilli may 
be taken up 
by the bugs, 
but transmis- 
sion has not 
been proven 
although it is 
suspected. It 
would take 
place by fecal 
contami- 
nation of 
wounds. 



Inoculated by 
bite of tick, 
probably by 
contamina- 
tion. 

Direct attack. 



Experimental 
transmission 
by bites of 
bugs. 

Transmission 
by mosquito 
bite. 



Transmission 
by mosquito 
bite. 

Transmission 
by fly bite. 

Transmission 
by mosquito 
bite. 



Transmitted by 
bite of mos- 
quito. 



Mechanical 
carrier. 



Mechanical 
carrier. 



Mechanical 
carrier. 



External para- 
site. 

Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



TABULATION OF DISEASES AND INSECT TRANSMISSION 483 



Disease 



Causative organism 



Insect transmitter 



Method of insect 
transmissions 



Nature of 
insect role 



Malaria subtertian (cont'd) 



Malaria, tertian 



Plasmodium vivax. 



Malaria, unclassified 



Plasmodium spp. 



Anopheles maculipal- 
pis indiensis 

" maculipennis 

" minimus aconi- 
tus 

" pseudopuncti- 
pennis 

" punctipennis 

" quadrimaculatus 

" rossii _ 

" sinensis 

" tarsimaculatus 

" theobaldi 

" turkhudi 

" umbrosus. 

Anopheles albimanus 

barbirostris 

bifurcatus 
" costalis 

crucians 

culicifacies 

fuliginosus 

funesta 

intermedium 

jesoensis 

Iistoni 

maculatus 

maculipalpis 

maculipennis 
" mediopunctatus 
" minimus 
" pharoensis 
' pseudomaculipes 
' punctipennis 
' quadrimaculatus 
" rossii 

sinensis 
' stephensi 
' superpictus 
' theobaldi 
4 turkhudi. 

More or less evidence 
has been pro duced 
against 
Anopheles aitkeni 
" algeriensis 

apicimaculata 
' arabiensis 
ardensis 
boliviensis 
braziliensis 
coustani 
culicifacies ser- 

gentii 
farauti 
grabhamii 
jamesii 
jeyporensis 
karwari 
maculipes 
martini 
mauritianus and 

var. paludis 
minimus and var. 

christophersi 
nimba 
pitchfordi 
puctulata 
pursati 
rhodesiensis 

d'thali 
sinensis pseudo- 

pictus 
turkhudi chau- 

doyei 
turkhudi myzo- 

myifacies 
vincenti 
willmori 



Transmitted by 
bite of mos- 
quito. 



Intermediate 
host. 



484 



SANITARY ENTOMOLOGY 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
insect role 


Mange, demodectic 


Demodex folliculorum 


Same as preceding 


Direct attack 


Parasite. 


(Seborrhea, blepharitis, 


" phylloides 


column. 


in hair folli- 




blackheads) 


" bovis 




cles. 




(acarine dermatosis) 










Mange, psoroptic 


Psoroptes communis ovis 


Same as preceding 


Direct attack in 


Parasite. 


(Acarine dermatosis) (sheep 


" bovis 


column. 


skin. 




scab, Texas itch, etc.) 


" equi. 








Mbori 


Castellanella evansi mbori. 


Tabanus taeniatus 


Transmission 


Intermediate 






" biguttatus. 


by bite. 


host. 


Measles 


Virus. 


Flies suspected. 


From sores. 


Mechanical 
carrier. 


Mediterranean coast fever. 










See Cattle fever 










Melanodermia 


Pediculus corporis 


Pediculus corporis 


Direct attack. 


External para- 




Phthirus pubis. 


Phthirus pubis. 




sites. 


Meningitis, cerebrospinal 


Diplococeus intracellularis 


Pediculus corporis. 


Taken up by 


Mechanical 




meningitidis. 




bite of louse 
deposited in 
feces. 


carrier. 


Miana, tick fever. 










See Fevers (tick) 










Murrina, equine 


Castellanella hippicum. 


Musca domestica 


Taken up by 


Mechanical 






Chrysomya 


flies from 


carrier. 






Sarcophaga. 


sores, carried 
to sores. 




Myiasis, blood-sucking larvae 


Auchmeromyia luteola 


Same as preceding 


Free living lar- 


Blood-sucking 




Chceromyia boueti 


column. 


vae attack 


parasites. 




chcerophaga 




mammals and 






Mydaea pici 




suck blood. 






Passeromyia heterochaeta 










Phormia azurea 










" chrysorrhcea 










" sordida. 








Myiasis of the head passages 


Cephalomyia maculata 


Same as preceding 


Flies deposit liv- 


True parasite 




Cephenomyia phobifer 


column. 


ing larvae in 


unternal). 




pratti 




nose. Larvae 






trompe. 




feed on tis- 






Oestrus ovis 




sues in head 






Rhincestrus hippopotami 

ElclSttllS 




passages. 






purpureus 








Myiasis intestinal and uro- 


Anthomyia disgordiensis 


Same as preceding 


Accidental in- 


Accidental par- 


genital 


Aphiochaeta ferruginea 


column. 


gestion. Some 


asite (inter- 




Cobboldia chrysidiformis 




of these spe- 


nal). 




elephantis 




c i e s may 






loxodontis 




breed in the 






Eristalis arbustorum 




intestines or 






" dimidiatus 




elsewhere. 






" tenax 










Pannia canicularis 










" scalaris 










Gastrophilus intestinalis^ 










haemorrhoidalis 




* 






nasalis 










Helophilus pendulinus 










Hydrotaea meteorica 










Muscina stabulans 










Mydaea vomiturationis 










Pharyngobolus africanus 










Piophila casei 










Pollenia rudis 










Sarcophaga haemorrhoidalis 








Myiasis, subdermal (truly par- 


Bengalia depressa 


Same as preceding 


Eggs laid on 


Parasite. 


asitic) (human, animal) 


Cordylobia anthropophaga 

rodhaini 
Cuterebra einasculator 
Gastrophilus intestinalis 
Hypoderma bovis 
" lineata 


column. 


skin. Larvae 
penetrate 
under tissue 
and burrow. 





TABULATION OF DISEASES AND INSECT TRANSMISSION 485 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
insect role 


Myiasis, subdermal (cont'd) 


Mydaea anomala 
" torquens 
Neocuterebra squamosa 
Oedemagena tarandi. 










Dermatobia hominis. 


The mosquito Pso- 


The fly larvae 


The mosquito 






rophora lutzi car- 


hatch while 


sucks blood 






ries the fly eggs to 


mosquito i s 


and carries 






the host. 


sucking blood 
and enter 
body, devel- 
oping in skin 
and emerging 
therefrom. 


a flesh para- 
site. 


Myiasis of the tissues (includ- 


Anastellorhina augur 


Same as preceding 


Deposition o f 


Scavenger and 


ing attack on eye, ear, nose, 


Anthomyia pluvialis 


column. 


eggs in tis- 


tissue de- 


wounds; screw worms, blow 


Calliphora dux 




sues and 


stroyer. 


flies, wool maggots) (human 


" erythrocephala 




wounds. Lar- 




animal) 


Chrysomya macellaria 

rufifacies 
Cynomyia spp. 
Lucilia argyrocephala 

" caesar 

" serenissima 

" sericata 

" tasmaniensis 
Microcalliphora varipes 

domestica 
Muscina stabulans 




vae develop 
at the ex- 
pense of the 
tissues. 




- 


Neopollenia stygia 
Ophyra nigra 
Phormia regina 


















Pycnosoma bezziana 










chloropyga 










flaviceps 










marginale 










megacephala 










putorium 










Sarcophaga aurifrons 










carnaria 










haemorrhoidalis 










lambens 










pyophila 










regularis 










Wohlfahrtia magnifica. 








Nagana 


Castellanella brucei 


Glossina morsitans 


Transmission 


Intermediate 






" brevipalpis 


by bite of 


hosts 






" pallidipes 


flies. 








" tachinoides 










" fusca 










Atylotus nemoralis 










Tabanus sp. 










Stomoxys calcitrans 










" glauca. 










Mansonia sp. 


Transmission 
by bite ex- 
perimental. 


Mechanical (?) 






Cimex lectularius. 


Experimentally 
transmitted 
by bite of 
bugs. 




Nematode, bovine 


Gongylonema scutatum. 


Aphodius coloraden- 


Insects swallow 


Intermediate 






sis 


eggs. Animals 


hosts. 






" fimetarius 


swallow in- 








femoralis 


sects. 








" granarius 










" vittatus 










Onthophagus hecate 










" pennsylvanicus 










Blattella germanica 










(experimental) 







486 



SANITARY ENTOMOLOGY 



Disease 



Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
insect rdle 


Spirocerca sanguinolenta 


Akis goryi 


Insects swallow 


Intermediate 




Copris hispanus 


eggs. Ani- 


host. 




Geotrupes douei 


mals swallow 






Gymnopleurus 


insects. 






sturmi. 








Scarabaeus sacer. 








" variolosus. 






Habronema megastoma. 


Musca domestica. 


Insects swallow 


Intermediate 






eggs. Animals 


host. 






swallow i n - 








sects. 




Habronema microstoma. 


Stomoxys calcitrans 


Insects swallow 


Intermediate 






eggs. Animals 


host. 






swallow 








insects. 




Habronema muscee. 


Musca domestica. 


Fly larvae swal- 
low eggs. An- 


Intermediate 






host. 






imals swallow 








insects. Pos- 








sibly also lar- 








vae leave pro- 








boscis of fly 
to at t a c k 














wounds and 








eyes. 




Acuaria spiralis. 


Porcellio laevis. 


Eggs eaten by 


Intermediate 






s o w b u gs . 


host. 






Sowbugs eat- 








en by chickens 




Filaria gallinarum. 


Hodotermes preto- 


Insects swallow 


Intermediate 




riensis. 


eggs. Chick- 
ens swallow 
insects. 


host. 


Gongylonema mucronatum. 


Ateuchus sacer 


Insects swallow 


Intermediate 




Chironitis irroratus. 


eggs. Animals 


host. 




Onthophagus bedeli 


swallow i n - 






Gymnopleurus 


sects. 






mopsus 








" sturmi. 








Geotrupes douei. 






Spirura gastrophila. 


Blaps sp. 


Insects swallow 


Intermediate 




Blaps strauchi 


eggs. Ani- 


hosts. 




Onthophagus spp. 


mals swallow 






Blatta orientalis. 


insects. 






Akis goryi 






Gongylonema pulchrum. 


Blattella germanica. 


Eggs eaten by 


Possible inter- 






roaches de- 


mediate host 






veloped to 








encysted lar- 








vae. 




Arduenna strongylina. 


Aphodius rufus cas- 


Insects swallow 


Intermediate 




taneus 


eggs. Ani- 


hosts. 




Onthophagus spp. 


mals swallow 
insects. 




Physocephalus sexalatus. 


Geotrupes douei 


Insects swallow 


Intermediate 




Onthophagus bedeli 


eggs. Ani- 


hosts. 




" nebulosus 


mals swallow 






Scarabaeus sacer 


insects. 






" variolosus 






Gongylonema brevispiculum 


Blaps sp. 


Insects swallow 


Intermediate 


probably 


Blaps strauchi. 


eggs. Animals 
swallow in- 
sects. 


host. 


Gongylonema neoplasticum. 


Blatta orientalis 


Insects swallow 


Intermediate 




Blattella germanica 


eggs. Ani- 


hosts. 




Periplaneta ameri- 


mals swallow 






cana 


insects. 






Tenebrio molitor. 







Nematode, canine 



Nematode, equine (granuloma) 



Nematode, equine (granuloma 



Nematode, equine 



Nematode, fowl 



Nematode, fowl 



Nematode hedgehog 



Nematode, hedgehog (fox, 
mongoose) 



Nematode, hog 



Nematode, hog 



Nematode, hog, donkey, 
dromedary 



Nematode, jerboa (probably) 



Nematode, rodent 



TABULATION OF DISEASES AND INSECT TRANSMISSION 487 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Xature of 
insect role 


Nematode, rodent 


Protospirura muris. 


Tenebrio molitor 
Xenopsylla cheopis. 


Insect swallows 
egg. Animal 
swallows in- 
sect. 


Intermediate 
hosts. 


Xuttalliosis, equine 


Xuttallia equi. 


Rhipicephalus 

evertsi 

and possibly 
Hyalomma aegyp- 

tium. 


Transmitted by 
bite of tick. 


Intermediate 
host. 


Ocular acariasis 


Dermanyssus gallinse. 


Dermanyssus gal- 
linse. 


Direct attack 
on cornea. 


Parasite. 


Ophthalmia nodosa. 

See Poisoning Lepidoptera 










Ophthalmia, purulent 




Musca domestica. 


From eye to eye. 


Mechanical 
carrier. 


Otoacariasis, human and animal 


Acaropsis mericourti 
Cheyletus eruditus 
Demodex folliculorum 
Dermanyssus gallins 
Ornithodoros megnini 
Otodectes cynotis 
Psoroptes cuniculi 
Rhyzoglyphus parasiticus. 


Same as preceding 
column. 


Direct attack 

on ear. 


Parasite. 


Pappataci fever 


Filterable virus. 


Phlebotomus papa- 
tasii. 


Transmission 
by bite of fly. 


Intermediate 
host. 


Paracolitis (summer diarrhoea 

Paralysis, infantile. 
See Poliomyelitis 


Bacillus paracoli. 


Musca domestica. 


Taken up by 
flies from 
stools. De- 
posited i n 
feces or food. 


Mechanical 
carrier. 


Paralysis, tick (human and 
animal) 


Amblyomma hebraeum 
Boophilus annulatus 

annulatus deco- 
loratus 
Dermacentor andersoni 
Ixodes holocyclus 

" pilosus 

" ricinus 
Ornithodoros coriaceus 
Rhipicephalus simus. 


Same as preceding 

column. 


Attachment of 
tick causes 
paralysis 
which may 
become fatal. 
Removal of 
tick head by 
excision ter- 
minates par- 
alysis. 


Parasite. 


Paratyphoid fever (A and B 


Bacillus paratyphosus (A 
and B). 


Musca domestica. 


Taken up by 
flies from 
stools. De- 
posited i n 
feces on food. 


Mechanical 
carriers. 


Pellagra 

Peritonitis. 
See Acariasis 


Unknown cause. 


Simulium spp. 

Stomoxys calcitrans 
have been sus- 
pected. 


Xo positive evi- 
dence. 




Pinworm, equine 


Oxyuris curvula (probably' 


Musca nebulo. 


Larva? swal- 
low eggs of 
worms. 


Possibly inter- 
mediate host. 


Piroplasmosis. 
See Cattle Fever 










Pityriasis 


Malassezia sp. 


Pediculus corporis. 


Manner of car- 
riage not dem- 
onstrated. 


Mechanical 
carrier. 



488 



SANITARY ENTOMOLOGY 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
Insect rdle 


Plague, bubonic 


Bacillus pestis. 


Ceratophyllus 


The bacillus is 


Mechanical 






acutus 


taken up 


carrier 






fasciatus 


from the 








" silantiewi 


blood by the 








Ctenocephalus canis 


flea, and may 








Leptopsylla musculi 
Pulex irritans 


be transmit- 








ted by regur- 








Pygiopsylla ahalae. 


gitation a t 








Xenopsylla cheopis. 


the time of 
biting, or by 
inoculaton 
through 
scratching in 
of infected 
feces. 








Musca domestica. 


Taken up by 
flies from 
stools. De- 
posited i n 
feces and 


Mechanical 
carrier. 
















food. 








Pediculus corporis. 


Experimental 
transmission 
obtained by 
subcutaneous 
inoculation of 
crushed lice. 


Mechanical 
carrier. 


Plague, rodent (sometimes hu- 
man, as Deerfly fever, Pah- 
vant Valley Plague) 


Bacterium tularense. 


Ceratophyllus acutus 


The bacillus is 
taken up from 
the blood. Ex- 
perimental in- 
fection has 
been obtained 
byinoculation 
ofcrushed 
fleas. 


Mechanical 
carrier. 






Musca domestica. 


Taken up from 

carcass. 


Mechanical 
carrier. 






Stomoxys calcitrans. 


Experimental 
transmission 
only has 
been obtain- 
ed by bite of 
fly and by in- 
oculation of 
crushed flies. 


Probably me- 
chanical car- 
rier. 






Chrysops sp. 


Inoculation by 
bite of fly is 
suspected. 


Mechanical 
carrier. 


Plica polonica 


Pediculus humanus. 


Pediculus humanus. 


Direct attack of 
lice o n t h e 
scalp. 


External para- 
site. 


Poisoning, bee, wasp and ant 


Apis mellifera 


Same as preceding 


The poison is 


Direct attack. 




Bombus spp. 


column. 


injected b y 






Pogonomyrmex barbatus 




sting of ovi- 






Polistes spp. 




positor. 






Vespa spp. 










Many other ants, bees 










and wasps. 








Poisoning, bug (used as food) 


Aspongopus nepalensis 


Aspongopus nepa- 


The bugs are 


Toxic poison- 






lensis. 


cooked and 
eaten asa del- 
icacy but 
cause severe 
rigors. 


ing. 


Poisoning, centipede 


Ethmostigmus spinosus 


Same as preceding 


The poison is 


Direct attack. 




Geophilus similis 


column. 


injected from 






Scolopendra angulata 
gigantea 




glands locat- 
ed in the head 






heros 




and having 






morsicans. 




their opening 
in a pair of 
venom claws 
lying beneath 
the head. 





TABULATION OF DISEASES AND INSECT TRANSMISSION 489 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
Insect role 


Poisoning, food (summer diar- 


Bacillus suipestifer. 


Musca domestica. 


Taken up from 


Mechanical 


rhoea) 






stools. De- 
posited on 
food. 


carrier. 


Poisoning, honey- 


Apis mellifera 


Same as preceding 


The honey of 


The role of the 




Melipona spp. 


column. 


these bees is 


bee is that of 




Trigona bipunctata 




contaminated 


contaminat- 




" amalthea 




by poisons 


ing its honey 




" ruficrus 




derived from 


which b e- 




" limao 




their foods, 
and may of- 
ten contain 
disease or- 
ganisms. 
Honey pois- 


comes food 
of man. 
















oning is often 










fatal to the 










natives of 










Central Amer- 










ica. 




Poisoning, kissing bug 


Melanolestes picipes. 


Melanolestes picipes 


Bite of insect. 


Direct attack. 


Poisoning, lepidopterous lar- 
val. (Browntail rash, oph- 


Automeris io 


Same as preceding 


Inflammation 


The insect's 


Gnethocampa pityocampa 
Euproctis chrysorrhoea 


column. 


of skin and 


r6le is neu- 


thalmia nodosa) 




mucous mem- 


tral. The in- 




Hemileuca maia 




brane caused 


jury is due to 




Lagoa crispata 




by spined or 


contact o f 




Lasiocampa pini 




barbed hairs 


the body 




Lymantria monacha 




containing 


with the 




Macrothylaeia rubi 




poison. 


hairs or to 




Megalopyge opercularis 






wind blown 




Porthesia similis 






hairs at the 




Porthetria dispar 






time of molt- 




Sibine stimulea. 






ing. 


Poisoning, scorpion 


Androctonus funestus 


Same as preceding 


The poison is 


Direct attack. 




Buthus afer 


column. 


injected b y 






carolinianus 




sting of poi- 






martensi 




sonous spine 






maurus 




at tip of tail. 






occitanus 










" quinquestriatus 
Centrurus exlicaude 


















Heterometrus maurus 










Isometrus europseus 










Prionurus amoureuni 










citrinus 








Poisoning, spider 


Chiracanthum nutrix 


Same as preceding 


The poison is 


Direct attach. 




Epeira diadema 


column. 


injected b y 






Latrodectes geometricus 




the mandibles 






hasseltii 




which c o n - 






" mactans 




tain a poison 






Lycosa narbonensis 




gland. 






tarantula 










Phiddipus audax 










Theraphosa javenensis 










Theridium lugubre 










" 13 — guttatum 










Trochosa singoriensis 








Poliomyelitis 


Filterable virus. 


Musca domestica. 


Taken up by fly 


Mechanical 


(Infantile paralysis 






from mucus 
discharges. 
Deposited in 


carrier. 
















feces. 










The virus taken 


Mechanical 






Cimex lectularius. 


up in blood 
by the bug. 
Experimental 

inoculation 
of crushed 
bugs pro- 
duccd disease 


carrier. 






Stomoxys calcitrans. 


A few experi- 
mental trans- 
missions b y 
bite. 


Mechanical 
carrier (?) 



490 



SANITARY ENTOMOLOGY 



Disease 



Causative organism 



Insect transmitter 



Method of insect 
transmissions 



Nature of 
Insect role 



Porrigo. 
See Favus 



Pseudoedema. malignant 



Pseudoparasitism of nasal and 
alimentary passages by cen- 
tipedes 



Pyodermia 

Redwater of cattle, British 



Red water. 

See Cattle Fever 



Relapsing fever, Abyssinian 



Relapsing fever, American 



Relapsing fever, Asiatic 



Relapsing fever, East African 



Bacillus "pseudoedema ma- 
ligno" Cao. 



Chaetechelyne vesuviana 
Geophilus carpophagus 
cephalicus 
electricus 
" similis 

Himantarium gervaisi 
Julus londinensis 

" terrestris 
Lithobius forficatus 
" melanops 

Polydesmus complanatus 
Scutigera coleoptrata 
Stigmatogaster subterraneus 



Pediculus corporis. 



Babesia divergens. 



Spiroschaudinnia sp. 



Blatta orientalis. 



Same as preceding. 



Pediculus corporis. 



Ixodes ricinus 
Hsemaphysalis cin- 
nabarina punctata, 



Ornithodoros savignyi 



Spiroschaudinnia novyi. 



Spiroschaudinnia carteri. 



Spiroschaudinnia rossi. 



Ornithodoros 

turicata 
" megnini 

" moubata. 

Argas persicus are 
suspected. 



Pediculus corporis. 



Ornithodoros mou- 
bata. 



Passes through 
intestinal 
tract intact. 
Infection by 
contamina- 
tion. 



Inflammation 
is caused in 
the nasal and 
alimentary 
passages due 
to the acci- 
dental e n - 
trance of cen- 
tipedes, prob- 
ably during 
sleep or in 
fresh vege- 
table foods. 



Direct attack. 



Transmitted by 
bite of tick. 



Experimental 
transmission 
by bite of 
tick. Trans- 
mission is 
probably by 
the washing 
into 'the 
wound of the 
organism in 
Malpighian 
excrement. 



Probably taken 
up by bite of 
tick and void- 
ed in Mal- 
pighian excre- 
ment, to be 
washed into 
w o u n d s by 
coxal fluids. 



Deposited in 
feces of lice. 



Probably taken 
up by bite of 
tick and void- 
ed in Mal- 
pighian excre- 
ment to be 
washed into 
wounds b y 
coxal secre- 
tions. 



Mechanical 
carrier. 



Direct attack. 



External para- 
site. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



TABULATION OF DISEASES AND INSECT TRANSMISSION 491 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
Insect role 


Relapsing fever, European 


Spiroschaudinnia recurrentis 


Cimex lectularius. 


Taken up by 
bug from 
blood and 
passed in 
feces. Inocu- 


Intermediate 
host. 
















lati o n by 










scratching at 










site of bite. 








Pediculus corporis 


Infection by 


Intermediate 






Polyplax spinulosus 


scratching in 


host. 






(experimental). 


feces or body 
of louse. 








Ornithodoros mou- 


Easily trans- 


Intermediate 






bata. 


mitted by the 
tick. Prob- 
ably taken up 
by the bite of 
tick and void- 
ed in Mal- 
pighian excre- 
ment, to be 
washed into 
wound by 
coxal fluids. 


host. 


Relapsing fever, North African 


Spiroschaudinnia berbera. 


Pediculus corporis. 


Infection by 
scratching in 
feces of louse. 


Intermediate 
host. 


Relapsing fever, Tropical Afri- 


Spiroschaudinnia duttoni. 


Ornithodoros mou- 


Taken up by 


Intermediate 


can 




bata. 


the bite of the 
tick and may 
be transmit- 
ted in subse- 
quent attach- 
ments of the 
adult, or of 
the second 
and even the 
third genera- 
tion of ticks. 
The organism 
is voided in 


host. 
















the Malpig- 










hian excre- 










ment and 










washed into 










the bite 










wound. 








Polyplax spinulosus 


Rat infected 


Intermediate 






(experimental). 


experiment- 
ally. 


host. 


Rhodesian Fever. 








See East Coast Fever 










Rocky Mountain Spotted 


Dermacentroxenus rickettsi 


Dermacentor 


Taken up by 


Intermediate 


Fever 




andersoni 
" variabilis 
" modestus 
" marginatus 
Amblyomma 

americanum. 


bite of tick 
and transmit- 
ted by bite of 
next genera- 
tion. 


host. 


Scab. 










See Mange (demodectic) 










Scabies (sarcoptic itch), (Aca- 


Sarcoptes scabiei hominis 


Same as preceding 


Direct attack of 


Parasitic. 


rine dermatosis of man and 


" ^ crustosse 


column. 


mites in skin. 




animals) 


" auchenise 
" bovis 
" canis 
" caprse 

dromedarii 
" equi 

leonis 
" ovis 
" suis 
" vulpis 
Notoedres cati cati. 
" muris 









492 



SANITARY ENTOMOLOGY 



Disease 



Causative organism 



Insect transmitter 



Method of insect 
transmissions 



Nature of 
insect role 



Scaly leg, chicken 
(acarine dermatosis) 

Scarlet fever 



Seborrhea. 

See Mange (demodectic) 



Septicaemia 



Septicaemia 
Septicaemia, rabbit 



Sleeping sickness 

Gambian and Nigerian 



Sleeping sickness, Rhodesian 



Smallpox 



Sore, Bagdad 

Sore, Biskra 
Sore, Orienta 



Cnemidocoptes mutans. 
Virus. 



Staphylococcus pyogenes vars. 
albus, aureus, citreus. 



Streptococcus. 
Bacillus cuniculicida. 



Castellanella gambiense. 



Castellanella rhodesiense. 



Virus. 



Leishmania tropica. 

Leishmania tropica. 
Leishmania tropica. 



Cnemidocoptes 

mutans. 

Flies suspected. 



Calliphora vomitoria 
Lucilia caesar 
Musca domestica 
Sarcophaga carnaria 
Tabanus sp. 



Stomoxys calcitrans. 
Musca domestica. 



Glossina palpalis 
palpalis 

fuscipes 
morsitans 
" fusca 
" longipennis 
pallidipes 
brevipalpis 
" tachinoides 
Stomoxys calcitrans 
Glossina morsitans 
palpalis 
" brevipalpis. 
Aedes argenteus. 



Flies. 



Aedes argenteus. 



Phlebotomus minu- 
tus africanus is 
suspected. 

Cimex lectularius 
" hemipterus. 



Musca domestica. 



Direct attack of 
mites on legs. 

Flies might car- 
ry virus from 
sore to sore. 



Insects take up 
from pus, car- 
ry in body or 
on legs. De- 
posit in feces 
on wounds. 

Found in body 
of fly. 

Flies take up 
from rabbit 
feces and dis- 
tribute i n 
their feces. 

Transmitted by 
fly bite. 



Transmitted by 
fly bite. 

Experimental 
transmission 
by mosquito 
bite. 

Flies have been 
found breed- 
ing in open 
lesions and 
can probably 
transmit the 
virUn lirough 
their feces. 

Mbsquitos took 
up parasites. 
Transmission 
unsuccessful. 

Transmission 
by bite of fly. 

Taken up by 
bug from 
blood and 
c a p a b 1 e of 
complete de- 
velopment in 
gut. No suc- 
cessful trans- 
mission. 

Transmission 
is probably 
effected b y 
fecal contam- 
ination. 

Can probably 
be taken up 
by flies from 
sores and de- 
posited in 
their feces on 
wounds or 
mucous mem- 
brane. 



Parasite. 



Mechanical 
carrier. 



Mechanical 
carriers. 



Mechanical 
carrier. 

Mechanical 
carrier. 



Intermediate 
host. 



Intermediate 
host. 

Mechanical (?) 



Mechanical 
carrier. 



Uncertain 



Mechanical 
carrier (?) 

Experimental 
intermediate 
host. 



Mechanical 
carrier, 



TABULATION OF DISEASES AND INSECT TRANSMISSION 493 



Disease 



Causative organism 



Insect transmitter 



Method of insect 
transmissions 



Nature of 
insect rdle 



Souma 



Duttonella cazalboui. 



Souma, Zambian 
Spirochsetosis, bovine 



Duttonella cazalboui pigritia. 



Spirosehaudinnia theileri. 



Glossina palpalis 

longipalpis 
morsitans 
tachinoides 
Stomoxys calcitrans 

nigra 
Tabanus biguttatus 
" taeniatus. 



Hsematopota per- 
turbans. 



Boophilus annulatus 

australis 
Rhi pi ceph al us 

evertsi. 



Spirochetosis, fowl, of North 
America 



Spirosehaudinnia granulosa. 



Argas pe'sicus. 



Spirochetosis, fowl, of Senegal 



Spirosehaudinnia neveuxii. 



Argas persicus. 



Spirochetosis, fowl, of South 
America 



Spirosehaudinnia marchouxi. 



Argas persicus 
reflexus 
Ornithodoros mou- 
bata. 



Transmitted by 
fly bite. 



Transmission 
by fly bite. 



Taken up by 
bite of tick. 
It appears 14 
days after in- 
oculation by 
larval tick. Is 
hereditary in 
B. decolora- 
tus. The man- 
ner of inocu- 
lation is not 
determined 
but is prob- 
ably by the 
washing into 
the wound of 
the organ- 
isms in the 
Malpighian 
excrement. 



Transmitted by 
bite of tick. 
The inocula- 
tion is prob- 
ably accom- 
plished by the 
washing into 
the wound of 
the organ- 
isms in t h e 
Malpighian 
excrement. 



Transmitted by 
bite of tick, 
probably by 
being washed 
into the 
wound by cox 
al fluid from 
the Malpig- 
hian excre- 
ta e n t in 
which it is 
voided. 



Taken up by the 
bite of tick 
and voided in 
Malpighian 
excrement 
which is 
washed into 
the wound 
made by bite, 
by c o x a 1 
fluids. Is 
probably her- 
editarily 
transmitted 
in the tick. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



494 



SANITARY ENTOMOLOGY 



Disease 



Spirochetosis, goose 



Spirochetosis. 

See Relapsing fever 

Splenic fever. 
See Cattle fever 

Suppurating wounds (blue- 
green pus) 



Surra 



Causative organism 



Spiroschaudinnia anserina. 



Bacillus pyocyaneus. 



Castellanella evansi. 



Tahaga (el dedab, zousfana) 

Tapeworm, canine and human 

Tapeworm, cattle and man 
Tapeworm, fowl 

Tapeworm, fowl 



Castellanella soudanense. 

Dipylidium caninum. 

Tsenia saginata. 
Choanotsenia infundibulum. 



Davainea cesticillus 
Davainea tetragona. 



Insect transmitter 



Argas persicus. 



Method of insect 
transmissions 



Musca domestica. 



Experimentally 

transmitted by 

Stomoxys calcitrans 

geniculate 

" nigra. 

Strong suspicion 

points to 
Tabanus tropicus 
" striatus 
" lineola 
" fumifer 
" partitus 
" vagus 
" minimus 
The following are al- 
so suspected: 
Lyperosia minuta 
Philaematomyia cras- 

sirostris 
Lyperosia exigua. 

Musca domestica. 



Aedes argenteus. 



Stomoxys calcitrans 

" nigra 

Atylotus nemoralis 

" tomentosus 

Trichodectes latus 
Ctenocephalus canis 
felis. 
Pulex irritans. 

Musca domestica. 



Musca domestica. 



Musca domestica. 



Transmitted by 
bite of tick. 
Transmission 
is probably 
the washing 
into the 
wound of the 
organism in 
Malpighian 
excrement. 



Taken up from 
wounds and 
carried to 
wounds. De- 
posited in 
feces on 
wounds. 

Transmitted by 
fly bite. 



Taken up from 
wounds and 
transmitted 
to wounds. 

Mosquitoes ex- 
perimentally 
took up or- 
ganism which 
persisted for 
hours. 

Transmission 
by bite of fly 
(experimental). 



Insect swallows 
eggs. Ani- 
mals swallow 
insects. 

Insect swallows 
eggs. Depos- 
its on food. 

Insect larvae 
swallow eggs, 
chicken swal- 
lows fly. 

Insect swallows 
eggs. Chicken 
swallows fly. 



Nature of 
insect r6le 



Intermediate 
host. 



Mechanical 
carrier. 



Intermediate 
host. 



Mechanical 
carrier. 



Mechanical 
carrier. 



Intermediate 
host. 



Intermediate 
host. 



Mechanical 
carrier. 



Intermediate 
host. 



Possibly inter- 
mediate host 



TABULATION OF DISEASES AND INSECT TRANSMISSION 495 



Disease 



Causative organism 



Insect transmitter 



Method of insect 
transmissions 



Nature of 
insect role 



Tapeworm, fowl. 



Tapeworm, human 



Tapeworm, rat and human 



Hymenolepis carioca. 



Davainea madagascariensis. 



Hymenolepis nana. 



Tapeworm, rodent and 
human 



Hymenolepis diminuta. 



Tetanus 



Thorn headed worm, rodent 
and human 



Thorn headed worm, pig and 
man 



Toxemia 



Trachoma 



Trench fever 



Trypanosomiasis, animal 



Trypanosomiasis, bat 



Trypanosomiasis, bovine 



Bacillus tetanus. 



Moniliformis moniliformis. 



Macracanthorhynchus hiru- 
dinaceus. 



Pediculus corporis 
Phthirus pubis. 



Filterable virus. 

Possibly Rickettsia quintana 



Castellanella dimorphon. 



Trypanosoma vespertilionis. 



Duttonella nanum. 



Stomoxys calcitrans 



Blatta orientalis. 



Ceratophyllus fasci- 

atus. 
Xenopsylla cheopis. 



Aids spinosa 
Anisolabis annulipes 
Asopia farinalis 
Fontaria virginiensis 
Julus sp. 
Scaurus striatus 
Tenebrio molitor. 

Ceratophyllus fasci- 

atus. 
Ctenocephalus canis 
Pulex irritans 
Xenopsylla cheopis. 



Dermatophilus pen- 
etrans. 



Blaps mucronata 
Penplaneta ameri- 
cana. 



Cetonia aurata 
Diloboderus abderus 
Melolontha vulgaris 
Phyllophaga arcuata 

Pediculus corporis 
Phthirus pubis. 

Musca domestica. 



Pediculus corporis. 



Glossina palpalis 

tachinoides 
" morsitans 
" longipalpis. 

Cimex pipistrelli. 



Glossina palpalis 

and possibly 
Glossina morsitans. 



Insect swallows 
eggs. Chicken 
swallows fly. 

The cysticercus 
has been 
found in these 
roaches. 

Insect swallows 
eggs. If the 
insect is the 
true interme- 
d i a t e host 
then infection 
is probably 
by the animal 
swallowing 
insect. 

Insect swallows 
eggs, animal 
swallows in- 
sect. 



The flea larva 
swallows the 
egg, which 
persists 
through met- 
amorphosis. 
The animal is 
infected by 
eating the 
flea. 

The attack of 
this flea fre- 
quently leads 
to attacks of 
tetanus. 

The larval stage 
has been 
found in these 
insects. 

Insects swallow 
eggs. A n i - 
mals eat in- 
sects. 

Direct attack. 
From eye to eye. 



Organism is de- 
p o s i t e d in 
feces of lice. 

Transmission 
by fly bite. 



Manner of 
transmission 
not demon- 
strated. 

Transmission 
by fly bite. 



Possibly inter- 
mediate host 



Mechanical car- 
rier or 
possibly bio- 
logical. 

Intermediate 
host (pos- 
sibly, but not 
proved). 



Intermediate 
host. 



Intermediate 
host. 



Mechanical 
carrier. 



Intermediate 
hosts. 



Intermediate 
hosts. 



External para- 
site. 

Mechanical 
carrier. 

Intermediate 
host 



Intermediate 
host. 



Intermediate 
host. 



Intermediate 
host. 



496 



SANITARY ENTOMOLOGY 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
insect role 


Trypanosomiasis, bovine 


Duttonella uniforme. 


Glossina palpalis. 


Transmission 
by bite. 


Intermediate 
host. 


Trypanosomiasis, bovine and 


Duttonella vivax. 


Glossina tachinoides 


Transmission 


Intermediate 


ovine 


s 


and probably 
Glossina palpalis 
" morsitans. 


by bite. 


host. 


Trypanosomiasis, crocodile 


Trypanosoma grayi. 


Glossina palpalis 


Transmission 


Intermediate 






brevipalpis. 


by bite. 


host. 


Trypanosomiasis, equine 


Castellanella annamense. 


Tabanidse 


Transmission 


Intermediate 






Hippoboscidae 


by bite. 


host. 






are suspected. 






Trypanosomiasis, fowl 


Trypanosoma (sens, lat.) 


Glossina palpalis. 


Transmission 


Intermediate 




gallinarum. 




by bite 


host. 


Trypanosomiasis, goat 


Duttonella caprae. 


Glossina brevipalpis 


Transmission 


Intermediate 






morsitans. 


by bite. 


host. 


Trypanosomiasis, rabbit 


Trypanozoon nabiasi. 


Ctenocephalus leporis 


Taken up by 


Intermediate 






Spilopsyllus leporis. 


the flea from 
the blood. 
Licked up by 
the rabbit in 
the feces of 
the flea. 


host. 


Trypanosomiasis, rodent 


Trypanozoon blanehardi. 


Ceratophyllus lave- 


Taken up by 


Intermediate 






rani. 


the flea from 
the blood. 
Licked up by 
the rodent in 
the feces of 
the flea. 


host. 


Trypanosomiasis, rodent 


Trypanozoon duttoni. 


Ceratophyllus hi- 


Taken up by 


Intermediate 






rundinis. 


the flea from 
the blood. 
Licked up by 
the rodent in 
the feces of 
the flea. 


host. 






Cimex lectularius. 


Experimentally 
fed to bed- 
bugs and ca- 
pable of de- 
velopment 
therein. 


Experimental 
intermediate 
host. 


Trypanosomiasis, rodent 


Trypanozoon rabinowitschi. 


Ctenocephalus canis 


Taken up by 
the flea from 
the blood. 
Licked up by 
the rodent in 
the feces of 
the flea. 


Intermediate 
host. 


Trypanosomiasis, rodent 


Trypanozoon lewisi. 


Ceratophyllus 


Taken up by 


Intermediate 






fasciatus 


the flea from 


host. 






hirundinis 


the blood. 








" lucifer 


Licked up by 








Ctenocephalus canis 


the rodent in 








Ctenophthalmus 


the feces of 








agyrtes 


the flea. 








Ctenopsylla musculi 










Pulex brasiliensis 










" irritans 










Xenopsylla cheopb. 










Polyplax spinulosus. 


Rat is infected 
by licking up 
insect's dejec- 
tions. 


Intermediate 
host. 






Cimex lectularius. 


Experimentally 
fed to bugs 
and complet- 
ed develop- 


Experimental 
intermediate 
host. 








ment. Inocu- 
lation of rec- 
tal contents 
produced dis- 
ease. 




Trypanosomiasis, simian 


Duttonella simiae. 


Glossina morsitans 


Transmitted by 


Intermediate 






brevipalpis. 


by bite. 


host. 



TABULATION OF DISEASES AND INSECT TRANSMISSION 497 



Disease 


Causative organism 


Insect transmitter 


Method of insect 
transmissions 


Nature of 
insect role 


Trypanosomiasis . 










See Aino, Baleri, Cbagas 










fever, Dourine, Horse sick- 










ness (Gambian), Mai de ca- 










deras, Nagana, Sleeping 










sickness, Souma, Surra, Ta- 










li aga 










Tsutsugamushi disease (-Jap- 


Filterable virus. 


Leptus akamushi. 


Transmission 


Intermediate 


anese river fever, Kedani dis- 






by bite of 


host. 


ease) 






mite. 




Tuberculosis 


Bacillus tuberculosis. 


Musca domestica. 


Taken up from 
sputum. De- 
posited on 
food. 


Mechanical 
carrier. 














Blatta orientalis. 


Passes through 
intestinal 
tract intact. 
Infection by 
contamina- 


Mechanical 
carrier. 


- 






tion. 




Tumors, sebaceous (in birds 


Harpyrynchus longipilus 


Same as preceding 


Direct attack in 


Parasite. 


and animals 


Psorergates simplex muscu- 

linus 
Myobia musculi. 


column. 


hair follicles. 




Typhoid fever 


Bacillus typhosus. 


Musca domestica. 


Taken up by 
larva or adult 
from stools. 
Survives met- 
amorphosis. 
Deposited in 
feces on food. 


Mechanical 
carrier pos- 
sibly also bi- 
ological. 






Pediculus corporis 


Organism was 


Mechanical 






" humanus. 


found in the 
lice. 


carrier. 


Typhus fever 


Filterable virus. 


Pediculus corporis. 


Organism is 


Intermediate 




Possibly Rickettsia prowa- 




deposited in 


host. 




zeki. 




feces of lice. 




Llrticaria 


Pediculus corporis. 


Pediculus corporis. 


Direct attack. 


External para- 
site. 


Urticariasis (grain itch, ery- 


Pediculoides ventricosus 


Same as preceding 


Direct attack in 


Parasite. 


thema urticaria) (acarine 


Tarsonemus uncinatus in- 


column. 


skin. 




dermatosis) 


tectus 
Crithoptes monunguiculatus. 








Uta 


Leishmania uta. 


Forcipomyia uta?. 


Transmission 


Mechanical 






" townsendi 


by bite. 


carrier (?) 






are suspected. 






Vanillismus 


Aleurobius farina? 


Same as preceding 


Direct attack in 


Parasite. 


(acarine dermatosis) 


Tyroglyphus siro 
Histiogaster entomophagus. 


column. 


skin. 




Verruga peruviana 


Bartonella bacilliformis (?) 


Phlebotomus verru- 


Transmission 


Intermediate 


(Carrion's disease) 




carum (?) 


by bite (?) 


host (?) 


Volhynian fever 


Rickettsia pediculi possibly 


Pediculus corporis. 


Experimental 
transmission 
obtained; 
method un- 
certain. 


Intermediate 
host. 


Whip worm 


Trichuris trichiura. 


Musca domestica 


Insects swallow 


Mechanical 






Borborus punctipen- 


eggs. Deposit 
eggs on food. 


carrier. 






nis. 




Withers, fistulous (equine) 


Dermacentor albipictus 


Same as preceding 


The attack of 


Produces le- 




venustus. 


column. 


the tick pro- 
duces necrotic 
spots which 
permit infec- 
tion. 


sions for en- 
trance of in- 
fection. 


Wyoming Intermittent fever. 










See Fevers (tick) 










Yaws 


Treponema pertenue. 


Musca domestica 


Taken up from 


Mechanical 






Oscinis pallipes 


ulcers, carried 


carrier. 






Sarcophaga (pos- 


to sores. 








sibly). 






Yellow fever 


Leptospira icteroides 


Aedes argenteus. 


Transmission 
hv bite. 


Intermediate 

host. 



INDEX 



Abscess, 69, 108, 115, 409 
Acanthocephala, 79, 389 
A canthocheilonema grassii, (Filaria), nem- 
atode, 75, 76, 89, 94 
perstans, (Filaria), human nematode, 74, 
75, 80, 81, 82, 89, 90, 91, 92, 93, 95, 
96, 261, 479 
recondittim, (Filaria), dog nematode, 76, 
80, 89, 92, 94, 357, 479 
Acanthomys spp., rodents, 353 
Acariasis, 474 
internal, 408 
ocular, 408 
sense organ, 408 
Acarina, ticks, mites, 88, 89, 403-429, 461 
Acarine dermatosis, 403 
Acaropsis mericourti, mite, 408, 487 
Achorion schoenleini, fungus, 289, 479 
Activity, zone of, 99 
Acuaria spiralis, fowl nematode, 66, 67, 

89, 486 
Adenitis, 69 

Aedes argenteus (calopus, fasciatus), yel- 
low fever mosquito, 70, 72, 74, 75, 80, 
89, 248, 249, 250, 251, 259, 260, 261, 
262, 266, 267, 269, 270, 272, 273, 477, 
479, 480, 482, 492, 494, 497 
gracilis, mosquito, 70, 80 
nemorosus. mosquito, 259, 482 
perplexus, mosquito, 262, 480 
pseudoscutellaris , mosquito, 262, 479 
scutellaris, mosquito, 70, 80, 262, 480 
sugens, mosquito, 261, 479 
sylvestris, mosquito, 249, 475 
vexans, mosquito, 261, 479 
Aeschna sp., dragon fly, 59, 87 
African relapsing fever tick (see Ornitho- 

doros moubata) 
Agamomermis culkis, mermithid, 262 
Aggrippina bona, gregarine, 355 
Aggrippinidae, 355 
Agrion sp., dragon fly, 59, 87 
Ainhum, 22, 373, 474 
Aino, 214, 474 
Akis goryi, beetle, 61, 62, 84, 486 

spinosa, beetle, 42, 54, 84, 495 
AUurobius farinae, mite, 405, 497 
Alhcreadinm isoporum, fluke, 59, 83, 87 
Allotrombidium fuliginosurn, mite, 404, 

477 
Amblyomma spp., ticks, 411, 424, 482 
americanum, Lone Star tick, 413, 436, 
491 



Amblyomma spp., cajennense, tick, 436 

hebraeum, tick, 410, 425, 436, 479, 480, 
487 

maculatum, Gulf Coast tick, 431 

testudiinis, tick, 414 
Amoebiasis, 474 
Amoebidae, 116, 117, 388 
Amoebina, 116, 117, 388 
Anabolia nervosa, caddice fly, 59, 83 
Anaphylaxis, 468, 469 
Anaplasma spp., piroplasmids, 414 

argentiwum, piroplasmids, 414, 474 

marginale, piroplasmids, 414, 474 
Anaplasmosis, 414, 474 

Argentine, 414 
Anastellorhina augur, fly, 181, 485 
Ancylostoma duodenale, hook worm, 122, 

480 
Ancylostomidae, 122 

Androctonns funestus, scorpion, 462, 489 
Anemia, avian, 249, 250 

canine, 420, 421, 474 

equine infectious, 211, 228, 230, 474 

jackal, 417, 474 

jerboa, 296, 355, 474 

owl, 475. 

palm squirrel, 297, 475 

rabbit, 475 

rat, 422, 475 

turtle, 475 
Anesthetic zone, 98, 102 
Anisolabis annulipes, earwig, 42, 54, 88, 

495 
Annoyance caused by insects, 20, 21 
Anopheles sp., mosquito, 252 

near claviger, 251 

aitkeni, mosquito, 253, 483 

albimanus, mosquito, 72, 255, 256, 257, 
258, 262, 285, 479, 480, 482, 483 

albipes (see A. albimanus) 

albirostris (see A. minimus aconitus) 

algeriensis, mosquito, 253, 255, 257, 261, 
479, 482, 483 

annulipes, mosquito, 255, 482 

apicimaculata, mosquito, 253, 483 

arabiensis, mosquito, 253, 255, 483 

arden-sis, mosquito, 253, 483 

argyrotarsis, mosquito, 255, 256, 262, 479, 
482 

barbirostris (Myzorhunchus), 70, 80, 255, 
257, 262, 479, 482, 483 

bifurcatus, mosquito, 73, 80, 257, 961, 
479, 483 



499 



500 



INDEX 



Anopheles sp., boliviensis, mosquito, 253, 

483 
braziliensis , mosquito, 253, 483 
claviger (see A. maculipennis) 
cohaesus (see A. minimus aconitus) 
costaMs (Pyretophorus), 70, 80, 255, 257, 

261, 479, 482, 483 
constant, mosquito, 254, 483 
crucians, mosquito, 255, 256, 257, 258, 

266, 267, 268, 270, 271, 272, 273, 482, 

483 
culicif acies mosquito, 255, 257, 482, 483 

sergentii, 254, 483 
farauti, mosquito, 254, 483 
febrifer (see A. minimus) 
formosaensis I (see A. minimus acon- 
itus) 

II, mosquito, 255, 482 
fragilis (see A. aitkeni) 
franciscanus (see A. pseudopuncti- 

pennis) 
fuliqinosus, mosquito, 255, 257, 258, 482, 

483 
funestus, mosquito, 255, 257, 258, 482, 483 
grabhamii, mosquito, 254, 483 
intermedium, mosquito, 258, 259, 483 
jamesii, mosquito, 254, 483 
jesoensis, mosquito, 258, 483 
jeyporensis, mosquito, 254, 483 
karwari, mosquito, 254, 483 
listoni, mosquito, 258, 483 
lutzii (see A. boliviensis) 
maculatus, mosquito, 256, 258, 482, 483 
maculipalpis , mosquito, 258, 483 

indiensis, 256, 483 
maculipennis, mosquito, 59, 72, 73, 75, 80, 

251, 256, 257, 258, 259, 261, 479, 480, 

482, 483 
maculipes, mosquito, 254, 483 
martini, mosquito, 254, 483 
mauritianus, mosquito, 254, 483 

paludis, 254, 483 
mediopunctatus , mosquito, 258, 259, 483 
minimus, mosquito, 254, 255, 258, 483 

aconitus, mosquito, 256, 483 

Christopher si, mosquito, 254, 483 
minutus (see A. sinensis) 
myzomyif acies (see A. turkhudi myzo- 
myif acies) 
nigerrvmus (see A. sinensis) 
nimba, mosquito, 254, 483 
peditaeniatus (see A. sinensis) 
pharoensis, mosquito, 258, 483 
pitchfordi, mosquito, 254, 483 
pseudomaculipes , mosquito, 258, 259, 483 
pseudopunctipennis, mosquito, 256, 266, 

271, 272, 274, 483 
punctipennis, mosquito, 256, 258, 259, 

266, 268, 271, 272, 274, 483 
punctulata, mosquito, 254, 483 
pursati, mosquito, 254, 483 
quadrvmaculatus , mosquito, 256, £57, 

258, 259, 266, 267, 271, 272, 274, 482, 

483 



Anopheles sp., rhodesiensis d'thali, mos- 
quito, 254, 483 
rossii (Myzomyia), mosquito, 59, 70, 81, 

256, 257, 258, 260, 261, 479, 482, 483 
sinensis (Myzorhynchus) , mosquito, 70, 

81, 256, 257, 258, 262, 479, 482, 483 
sinensis peditaeniatus, mosquito, 70, 81 
sinensis pseudopictus, mosquito, 73, 81, 

255, 261, 262, 483 
stephensi, mosquito, 251, 257, 258, 482 
superpictus (Myzcmyia), mosquito, 73, 

81, 255, 261, 479, 483 
tarsimaculatus , mosquito, 256, 285, 483 
theobaldi, mosquito, 256, 257, 258, 482, 

483 
turkhudi, mosquito, 256, 258, 483 
chaudoyei, mosquito, 255, 483 
hispaniola, mosquito, 258 
myzomyif acies, mosquito, 255, 257, 482, 

483 
umbrosus, mosquito, 256, 483 
vincenti, mosquito, 255, 483 
wilhnori, mosquito, 255, 483 
ziemanni (see A. mauritianus) 
Ant bear, 196 

Antelope (see Tragelaphus spekei) 
Anthomyia disgordiensis, fly, 193, 484 

pluvialis, fly, 180, 485 
Anthrax, 49, 109, 110, 115, 209, 210, 228, 

230, 249, 384, 470, 475 
Anthrenus museorum, beetle, 470, 475 
Aphaniptera, fleas, 79, 80 
Aphiochaeta ferruginea, fly, 192, 484 
Aphodius color adensis , beetle, 62, 84, 485 
femoralis, beetle, 62, 84, 485 
flmetarius, beetle, 62, 84, 485 , 
granarius, beetle, 84, 485 
rufus castaneus, beetle, 64, 84, 486 
vittatus, beetle, 62, 84, 485 
Apis mellifera, honey bee, 467, 468, 488, 

489 
Apoxeraenosis, 98, 101 
Aquaria, 282 
Arachnida, 461 
Araneae, 461 
Ar duenna strongylina, pig nematode, 64, 

84, 85, 486 
Argas spp., ticks, 424 
brumpti, tick, 409 
miniatus, tick, 432 
persicus, fowl tick, 418, 420, 423, 445, 

446, 479, 490, 493, 494 
reflexus, tick, 409, 411, 419, 423, 432, 480, 

493 
vespertilionis, tick, 423 
Armadillo, 393 

Army diseases carried by insects, 43-48 
Army sanitation, 43-48 
Arsenic dip, 442 
Arsenic wash, 337 
Ascariasis, 121, 122, 475 
Ascaridae, 121 

Ascaris lumbricoides, human nematode, 68, 
96, 106, 121, 475 



INDEX 



501 



Ascomycetes, 289 

Asopia farinalis, meal moth, 42, 54, 83, 495 

Asphyxia, 408 

Aspongopus nepalensis, bug, 469, 488 

Ateles pentadactylus, monkey, 302 

Ateuchus sacer (see Scarabaeus) 

Attagenus pellio, beetle, 470, 475 

Atylotus spp., horseflies, 228 

nemoralis, horsefly, 214, 217, 485, 494 

rufidens, horsefly," 211, 474 

tomentosus, horsefly, 215, 217, 478, 494 
Auchmeromyia spp., flies, 228 

luteola, Congo floor maggot, 195 
Automeris >io, moth, 467, 489 

Babesia spp., piroplasmids, 414 
argentinum, piroplasmid, 414, 475 
bigeminum, piroplasmid, 414, 475 
bovis, piroplasmid, 414, 415, 475 
caballi, piroplasmid, 415, 475 
canis, piroplasmid, 415, 424, 434, 475 
divergent, piroplasmid, 417, 490 
gibsoni, piroplasmid, 417, 475 
minense, piroplasmid, 417, 475 
ovis, piroplasmid, 417, 436, 475 

Babesiasis, bovine, Argentine 414, 475 
canine, 415, 417, 476 
hedgehog, 417, 475 
jackal, 475 

Bacillus of Koch-Weeks, bacterium, 109, 
477 
of Morgan, bacterium, 109, 478 
A of Ledingham, bacterium, 109 
acidi lactici, bacterium, 109 
aerogenes capsulatus, bacterium, 109, 480 
anthracis (see Bacterium) 
cloacae, bacterium, 110 
coli, bacterium, 110, 384, 385, 387, 477 
coli anaerogenes, bacterium, 110 
coli communior, bacterium, 110 
coli communis, bacterium, 110 
coh mutabilis, bacterium, 110 
colisimile, bacterium, 110 
cuniculicida, bacterium, 110, 492 
diphtheriae, bacterium, 111, 478 
dysenteriae, bacterium, 478 
dysenteriae, Flexner, bacterium, 111 
dysenteriae, Shiga, bacterium, 111 
dysenteriae Y Hiss and Russell, bac- 
terium, 111 
enteritidis, bacterium, 111 
fecalis alkaligenes, bacterium, 111 
fluorescens liquifaciens, bacterium, 111, 

384 
fluorescens nonliquefaciens, bacterium, 

111, 385 
gasoformans, nonliquefaciens, bacterium, 

112 
griinthal, bacterium, 112 
icteroides, bacterium, 260 
lactis acidi, bacterium, 112 
lactis aerogenes, bacterium, 112 
leprae, bacterium, 112, 392, 481 
mallei, bacterium, 112 



Bacillus megatherium, bacterium, 385 
neapolitanus, bacterium, 112 
necrophagus, bacterium, 482 
necrophorus, bacterium, 411, 475 
oxytocus perniciosus , bacterium, 112 
paracoli, bacterium, 112, 487 
paradysenteriae, bacterium, 111 
paratyphosus A, bacterium, 112, 487 
paratyphosus B, bacterium, 112, 487 
pestis, bacterium, 112, 350, 351, 360, 392, 

393, 488 
prodigiosus, bacterium, 112 
proteisimile , bacterium, 386 
proteus mirabilis, bacterium, 113 
proteus vulgaris, bacterium, 113 
proteus zenkeri, bacterium, 113 
pseudoedema maligno, bacterium, 386. 

490 
pyocyaneus, bacterium, 113, 494 
radiciformis, bacterium, 113, 386 
ruber kielensis, bacterium, 113 
schaferi, bacterium, 113 
sepUcus agrigenus, bacterium, 113 
similcarbonchio, bacterium, 113, 386 
subtilis, bacterium, 113, 387 
suipestifer, bacterium, 114, 260, 489 
tetani, bacterium, 373, 495 
tifosimde, bacterium, 114, 387 
tracheiphilus, bacterium, 470 
tuberculosis, bacterium, 114, 387, 497 
typhi-exanthematici, bacterium, 292 
typhosus, bacterium, 114, 387, 393, 497 
vesiculosus, bacterium, 114 
xerosis, bacterium, 114, 115 
Bacteriaceae, 109-114, 209, 210, 249, 350, 

351, 384-387, 392, 393 
Bacterium anthracis, bacterium, 109, 110, 
113, 122, 209, 210, 249, 384, 386, 
475 
cholerae-gallinarum, bacterium, 384, 477 
tularense, bacterium, 114, 209, 351, 488 
Baleri, 216, 230, 475 
Barns, 37 

Barn yards, 167-170 
Bartonella bacilli forrmis, microorganism, 

211, 497 
Bat, 59, 395 

Bat (see Phyllostomus sp.) 
Bath outfits, 317, 318 
Bays, 276 

Bedbug (see Cvmex spp.) 
bite, 401 
control, 401 
Bee disease (see Nosema apis) 
Beef tapeworm (see Taenia saginata) 
Bengalia depressa, fly, 190, 484 
Beri-beri, 291 

Bibliography, 89-96, 123-125, 137, 151-15:. 
196-199," 220-222, 235, 246, 263-265, 
274, 285, 297-300, 311, 328, 329, 348, 
358-359, 371-373, 390, 401, 402, 427- 
429, 438, 439, 449, 459, 460, 470, 471 
Bilharziosis, 120, 122 
Biliary fever, equine, 436, 475 



502 



INDEX 



Binucleata, 117-119, 212-219, 249-259, 294, 

352-355, 388, 393-398, 414 
Bird lice, 288 

Blaberus sp., cockroach, 376 
Blackheads, 407, 411, 475 
Blaps sp., beetle, 63, 84, 486 

sp., near appendiculata, beetle, 62, 84 

appendiculata, beetle, 62 

emondi, beetle, 62, 84 

mortisaga, beetle, 55 

rrmcronata, beetle, 79, 84, 495 

strauchi, beetle, 62, 63, 84, 486 
Blatta sp., cockroach, 388 

orientalis, cockroach, 55, 60, 62, 63, 88, 
376, 377, 378, 379, 383, 384, 385, 386, 
387, 388, 389, 475, 477, 478, 486, 490, 
495, 497 
Blattella germanica, cockroach, 55, 62, 63, 
88, 376, 377, 378, 384, 388, 389, 485, 
486 

lapponica, cockroach, 388 
Blepharitis, 288, 407, 475 
Blood-sucking fly larvae, 195, 196 
Bodonidae, 117 

Body louse (see Pediculus corporis) 
Bombus spp., bumble bees, 467, 488 
Boophilus spp., ticks, 424, 426 

awtmlatus, cattle tick, 410, 414, 434, 435, 
441, 476, 487 

anrmlatus australis, cattle tick, 414, 474, 
475, 476, 493 

anmilatus decoloratus, cattle tick, 415, 
420, 474, 476, 487 

microphis (see B. am/rmlatus australis) 
Borax, 381 
Borborus pwictipennis (Limosma), fly, 

121, 122, 475, 497 
Bots, 182-186 
Bouba, 219, 251 

Bovine trypanosomiasis, 217, 218 
Bronchial inflammation, 408 
Browntail rash, 466, 475 
Bubonic plague (see Plague, Bubonic) 
Buffalo gnats (see Sinmlium spp.) 
Bug-borne diseases, 392 
Bugs, 391-402 
Bursarinidae, 388 
Buthus afer, scorpion, 462, 489 

carolirricmus, scorpion, 462, 489 

martensi, scorpion, 462, 489 

maurus, scorpion, 462, 489 

occitanus, scorpion, 462, 489 

quinquestriatus , scorpion, 462, 489 

Cabbage snake (see Mermithidae) 
Caddice flies (see Trichoptera) 
Calliphora spp., flies, 177, 453 
dux, fly, 179, 485 

erythrocephala, fly, 105, 110, 111, 117, 
130, 131, 132, 140, 143, 147, 148, 151, 
180, 475, 478, 485 
vomitoria, fly, 105, 108, 109, 110, 111, 112, 
113, 114, 115, 120, 130, 131, 133, 140, 
143, 148, 386, 475, 477, 492 



Calopteryx virgo, dragon fly, 59, 87 

Camel, 405 

Camel head bot (see Cephalomym macu- 
lata) 

Camel trypanosomiasis, 215 

Canary, 259 

Candy factories, 41 

Canis aureus, jackal, 356 

familiaris, dog, 260, 344, 373, 405, 408, 
414, 415, 416, 420, 421, 436 

Canthariasis, 22 

Cantharidin, 42 

Cantharis flavicornis, beetle, 469, 478 
vestitus, beetle, 469, 478 

Capybara, 393 

Carassius auratus, goldfish, 282 

Carbon bisulphide, 324, 326, 380 

Carcass disposal, 161, 162, 200, 201, 202 

Carceag, 417, 475 

Carpoglyphus alieims, mite, 474 

Carrion's disease, 211 

Castellanella annamense, trypanosome, 214, 
496 
brucei, trypanosome, 214, 250, 393, 474, 

485 
dimorphon, trypanosome, 214, 495 
equiperdum, trypanosome, 215, 478 
eqwinwm, trypanosome, 393, 482 
evansi, trypanosome, 119, 215, 250, 494 
evansi mborii, trypanosome, 215, 484 
gatmbiense, trypanosome, 215, 250, 492 
kippicum, trypanosome, 119, 484 
nigeriense (see C. gambiense) 
pecaudi, trypanosome, 216, 475 
rhodesiense, trypanosome, 217, 250, 492 
soudanense, trypanosome, 217, 494 

Castor-bean tick (see Ixodes riciims) 

Castor oil, 382 

Cat, 344, 373, 408 

flea (see Ctenocephalus felis) 
nematode (see Spirura gastrophila) 

Catarrhal inflammation, 408 

Caterpillars, 78 

Cattle (see also bovine), 373, 405, 408, 414 
fever, Southern or Texas, 414, 475 
head bot (see Rhinoestrus nasalis) 
lice, 330-339 

nematode (see Gongylonema scutatum) 
nematode (see Oncocerca sp.) 
nematode (see Oncocerca gibsotii) 
nematode (see Oncocerca lienalis) 
nematode (see Setaria labiato-papillosa) 
sprays, 335-337 
susceptibility to lice, 331 

Centipede poisoning, 464-466 

Centipedes in nasal cavities, 466 

Centrarchus macropterus, fish, 282 

Centrums exlicaude, scorpion, 462, 489 

Cephalacanthus monacanthus, worm, 78, 86 
triacanthus, worm, 78, 85 

Cephalom/yia maculata, bot, 194, 484 

Cephalopsis titillator (see Cephalomyia 
maculata) 

Cephenomyia spp., bots, 176 



INDEX 



503 



Cephenomyia spp., phobifer, bot, 194, 484 

pratti, bot, 194, 484 

trompe, bot, 194, 484 
CeratophyUus acutus, flea, 351, 360, 363, 
365, 488 

anisus, flea, 360, 364 

fasciatus, rat flea, 54, 55, 56, 79, 94, 350, 
351, 352, 354, 355, 357, 360, 361, 364, 
488, 495 

gallinae, flea, 363 

hirundinis, flea, 352, 496 

laverani, flea, 352, 496 

lucifer, flea, 352, 355, 496 

silantiewi, flea, 351, 365, 488 
Ceratopogon spp., midges, 224 
Ceratopogoninae, 223 
Cesspools, 282 

Cestoda, tapeworms, 53-57, 88, 297 
Cestoidea, tapeworms, 120, 355, 356, 357, 

389 
Cetonia aurata, beetle, 79, 85, 495 
Chaetechelyne vesuviana, centipede, 466, 

490 
Chactopteryx villosa, caddice fly, 59, 83 
Chagas fever, 393, 414, 475 
Cheese bacteria, 113 

maggot (see Piophila casei) 
Chelidon urbica, bird, 252 
Cheyletus eruditus, mite, 408, 487 
Chicken (see also Fowl), 405, 406, 407, 408 

house and yard, 173, 174, 445, 446, 447 

roosts, 445, 446 

tick (see Argas persicus) 
Chiggers, 22, 404, 477 
Chigoe (see Dermatophilus penetrans) 
Children, protection from insects, 37 
Chilopoda, 461 

Chiracanthum nutrix, spider, 464, 489 
Chironitis irroratus, beetle, 63, 85, 486 
Chironomidae, 223 

Chironomus plumosus, midge, 59, 81 
Chlorocvanogen, 325 
Chlorpicrin, 324, 326 

Choanotaenia infundibulum, fowl tape- 
worm, 53, 56, 57, 82, 120, 122, 494 
Choeromyia spp., flies, 229 

boueti, fly, 196, 484 

choerophaga, fly, 196, 484 
Cholera, 49 

Asiatic, 115, 387, 477 

fowl, 384, 477 

hog, 116, 122, 211, 477 
Chordodes alpestris, horse-hair worm, 79 
Chorioptes equi (symbiotes), mite, 405, 481 

symbiotes (see C. equi) 
Chrysoconops fuscopennatus, mosquito, 75, 

81 
Chrysomya sp., fly, 119, 484 

chloropyga, fly, 180 

macellaria, screw worm fly, 132, 133, 134, 
135, 140, 143, 149, 150, 175, 177, 178, 
179, 196, 453, 485 

rufifacies, fly, 181, 485 
Chrysomyza spp., flies, 453 



Chrysops spp., horseflies, 81, 93, 209, 228, 
488 
centurionis, horsefly, 71, 81, 210, 220, 

475, 480 

dimidiata, horsefly, 71, 81, 220, 480 

japonicus, horsefly, 211, 474 

longicornis, horsefly, 71, 81 

silacea, horsefly, 220, 480 
Chrysozona spp., horseflies, 228 

pluviatilis, horsefly, 211, 474 
Chvluria, 69 
Ciliata, 388 
Cimex spp., bedbugs, 251 

boueti, bedbug, 391, 394, 400, 476 

columbarius, bedbug, 400 

hemipterus, bedbug, 294, 391, 394, 395, 
396, 398, 400, 476, 481, 492 • 

hirundinis, bedbug, 400 

lectularms , bedbug, 294, 296, 391, 392, 
393, 394, 395, 396, 397, 398, 399, 400, 

476, 481, 482, 485, 489, 491, 492, 496 
pipistrelli, bedbug, 395, 400, 495 
rotundatus (see C. hemipterus) 

Cimicidae, 399 

Cisterns, 282 

Citellus beecheyi, ground squirrel, 351 

City sanitation, 39-41 

Clayton gas, 325 

Clepsidrina blattarum, gregarine, 388 

serpentula, gregarine, 388 
Climate and life, 97-104 
Clinostomum sp., trematode, 260 
Clipping of hair of cattle, 334 
Cloeon dipterum, mayfly, 59, 87 
Cnemidocoptes gallinae, mite, 478 

mutans, mite, 405, 406, 407, 492 
Cnethocampa pityocampa, moth, 467, 489 
Cobboldia chrysidiformis, bot, 193, 484 

elephant is, bot, 193, 484 

loxodontis, bot, 193, 484 
Coccaceae, 107-109, 210, 211, 289, 290, 383, 

384 
Coccidiidea, 388 
Cockroach control, 380-382 
Cockroaches, 51, 374-390, 458 
Coleoptera, beetles, 59, 84, 85, 86, 469, 470 
Colitis, 477 

Columba livia, dove, 212, 213, 219 
Comfort stations, 39 
Conorhinus spp. (see Triatoma) 
Conchuda (see Ixodes bicornis) 
Conjunctivitis, 109, 115, 477 

phlyctenular, 290, 477 
Cootie (see Pediculus corporis) 
Copris hispanus, beetle, 61, 85, 486 
Coprophagous insects, 51, 52 
Cordulia sp., dragon fly, 59, 87 
Cordylobia anthropophaga, fly, 188, 189, 
204, 484 

rodhaiwi, fly, 189, 198, 484 
Cow pasture, 233 
Crab louse (see Phthirus pubis) 
Creolin, 336 
Cricetus spp., rodents, 354 



504 



INDEX 



Crickets, 78 

Crithidia calliphorae, leptomonid, 117 
ctenophthalm\i, leptomonid, 354 
fasciculata, leptomonid, 251 
haemaphysalidis, leptomonid, 417 
hyalommae, leptomonid, 417 
hystrichopsyllae, leptomonid, 354 
melophagia, leptomonid, 219 
muscae-domesticae , leptomonid, 117 
nycteribiae, leptomonid, 219 
pangoniae, leptomonid, 219 
pulicis Porter, leptomonid, 354 
pulicis Wenyon, leptomonid, 354 
tenuis, leptomonid, 219 

Crithoptes mommy uiculosus, mite, 404, 497 

Crocodile trypanosomiasis, 218 

Crossbill, 408 

Crow, 259 

Cryalgesia, 100 

Cryesthesia, 100 

Cryptococcus farciminosus, microorganism, 
411, 482 

Ctenocephalus ccmis, dog flea, 53, 54, 55, 

76, 79, 80, 351, 352, 354, 355, 356, 357, 

360, 362, 363, 479, 481, 488, 494, 495, 

496 

felis, cat flea, 53, 76, 80, 355, 357, 360, 

363, 479, 494 
leporis, rabbit flea, 353, 496 

Ctenophthalmus agyrtes, flea, 352, 354, 355, 
360, 365, 496 
assimihis, flea, 354 

Ctenopsylla musculi, flea, 352, 355, 364, 496 

Culex sp., mosquito, 249, 251, 261, 268 
albopictus (see Aedes scutellanis) 
cantator, mosquito, 249 
ciliaris (see C. quinquefasoiatus) 
fatigans (see C. quinquefasciatus) 
gelidus, mosquito, 70, 81, 262, 480 
jenningsi, mosquito, 269 
ludlowi, mosquito, 250 
malariae, mosquito, 73, 81, 261, 479 
microcmnulatus, mosquito, 262, 480 
nigrithorax skusei (see C. quinquefascia- 
tus) 
penicillaris, mosquito, 73, 81, 261, 479 
pipiens, mosquito, 70, 73, 82, 93, 248, 
249, 250, 251, 25Q, 259, 261, 284, 475, 
479, 482 
quinquefasciatus, mosquito, 59, 70, 72, 82, 
248, 250, 251, 252, 259, 260, 261, 262, 
266, 267, 270, 272, 273, 477, 479, 480, 
482 
sitiens, mosquito, 70, 82, 262, 480 
sollicitans, mosquito, 249, 262, 273 
taeniatus (see Aedes argenteus) 
vexans (see Aedes) 

Culicidae, 219, 228 

Culicoides spp., midges, 224 

Culiseta annulata, mosquito, 249, 475 

Cuterebra emasculator, bot, 187, 484 
fontinella, bot, 187 

Cyanide fumigation, 325, 326 

Cyclophyllidea, 120, 247, 355, 356, 357 



Cyclopodxia sykesi, fly, 219 

Cynomolgus cynocephalus, monkey, 295 

Cynomyia spp., flies, 177, 485 
cadaverma, fly, 132, 453 

Cyprinodon variegatus, fish, 282 

Cyprinoid fish flukes, 59 

Cypselus affinis, swift, 72 

Cytoleichus banksi, mite, 408, 474 
rmdus, mite, 408, 474, 481 
sarcoptoides, mite, 408, 474, 481 

Davainea cesticillus, fowl tapeworm, 57, 82, 
89, 120, 489 

madagascarienMs, tapeworm, 388, 495 

tetragona, fowl tapeworm, 57, 82, 89, 
120, 494 
Deer fly fever, 209, 477, 488 
Deer head bots (see Cephenomyia) 
Defecation, 39 
Delousing, 314-316 
Demodex bovis, mite, 407, 484 

folliculorum, mite, 407, 408, 411, 476, 
484, 487 

phylloides, mite, 407, 484 
Dengue, 48, 248, 262, 477 
Depluming mite, chicken, 478 
Dermacentor spp., ticks, 424 

albipictus, tick, 412, 436, 497 
Dermacentor andersoni, Rocky Mt. spotted 
fever tick, 22, 409, 410, 412, 413, 436, 
437, 438, 443, 479, 487, 491 

marginatus, tick, 413, 491 

modestus, tick, 412, 491 

nitens, tick, 418, 431, 436, 478 

occidentals, tick, 412, 425, 436 

reticulatus, tick, 409, 415, 417, 418, 425, 
476, 478 

variabilis, tick, 412, 413, 425, 436, 491 

vewustus (see also D. andersoni), 409, 
497 
Dermacentroxenus rickettsi, microorganism, 

413, 491 
Dermanyssidae, 422 

Dermanyssus gallinae, mite, 404, 408, 422, 
474, 487 

hirundinis, mite, 404, 474 
Dermaptera, 88 
Dermatitis, 286, 290, 469 

beetle, 478 

equine granular, 121, 122 
Dermatobia sp., fly, 175 

cyaniventnis (see D. hominis) 

hominis, fly, 22, 187, 197, 199, 204, 485 

noxialis (see D. hominis) 
Dermatophilus penetrans, chigoe, 22, 360, 

365, 373, 474, 495 
Dermatosis, 22, 403 

papular eczematous, 404 
Dermestes vulpinus, beetle, 470, 475 
Diabrotica vittata, beetle, 470 
Diarrhea, 49 

fowl, 387, 478 

infantile, 109, 115, 478 

infantile dysenteric, 111, 115 



INDEX 



505 



Diarrhea, summer, 112, 114, 478 

Diloboderus abderus, beetle, 79, 84, 495 

Dip, 442, 443 

Diphtheria, 111, 115, 478 

Dvplobacillus exanthematicus, bacterium, 

292 
Diplococcus sp., microorganism, 292 
gonorrhoeae, microorganism, 108, 480 
intra-cellularis meningitidis , microorgan- 
ism, 108, 289, 484 
pemphigi contagiosi, microorganism, 289, 
481 
Diplocystis schneideri, coccidian, 388 
Dipodillus campestris, jerboa, 63 
Diptera, flies, 59 
Dipylidium caninwm, dog tapeworm, 53, 

54, 80, 86, 297, 355, 356, 494 
Dirofilaria intimitis, nematode, 73, 80, 81, 
82, 89, 261, 479 
repens, dog nematode, 74, 76, 80, 89, 
261, 479 
Disease, how carried by insects, 19-24 

transmission, how to prove, 25-33 
Diseases carried or caused by beetles, 469- 
470 
carried or caused by bugs, 392-399 
carried or caused by caterpillars, 466, 

467 
carried or caused by cockroaches, 383- 

390 
carried or caused by fleas, 350-359 
carried or caused by flies, 104-125, 209- 

222. 
carried or caused by lice, 286-360 
carried or caused by mites, 402-429 
carried or caused by mosquitoes, 247-265 
carried or caused by ticks, 402-429 
carried to food by 'insects, 22 
carried to wounds by insects, 23 
inoculated by insects, 23 
Dispharagus nasutus, nematode, 68, 94 
Ditching, 276, 277 

Dog (see Canis familiaris, and can'ine) 
Dog flea (see Ctenocephalus canis) 
louse (see Trichodectes latus) 
nematode (see Acanthocheilonema gras- 

sii) 
nematode (see Acanthocheilonema recon- 

ditum) 
nematode (see Dirofilaria immitis) 
nematode (see Dirofilaria repens) 
nematode (see Spirocerca sanguinolenta) 
Donkey nematode (see Physocephalus sex- 

alatus) 
Dourine, 215, 228, 230, 478 
Dragon flies (see Odonata) 
Drainage, 37, 39, 277-279 
Dromedary, 405 

nematode (see Physocephalus sexalatus) 
trypanosomiasis, 217 
Drosophila confusa, fly, 117, 118 
Drusus trifidus, caddice fly, 59, 83 
Dry cleaning, 320, 321 
Duttonella caprae, trypanosome, 217, 496 



Duttonella cazalboui, trypanosome, 217, 493 

cazalboui, pigritia, trypanosome, 217, 493 

congolense, trypanosome, 217, 480 

namxm, trypanosome, 217, 495 

pecorum, trypanosome, 218 

svmiae, trypanosome, 218, 496 

uniforme, trypanosome, 218, 496 

vivax, trypanosome, 218, 496 
Dysentery, 49 

amoebic, 117, 478 

baciiiary, 111, 115, 478 

Lamblian, 117, 478 

East Coast fever, 417, 436, 447, 478 
Echidnophaga gallinaceus, flea, 360, 365, 

366 
Echinorhynchus sp., worm, 91 
Eczema, 287, 290, 478 
Effective temperature, 99-104 
Eimer'iidae, 388 
Elassoma zonatum, fish, 282 
El dedab, 217 
Elephant bots, 193 

foot bot (see Neocuterebra squamosa) 
Elephantiasis, 69, 261, 478 
Elk, 436 
Endamoeba blattae, amoebid, 388 

coli (see Loschia) 
Enneacanthus gloriosus, fish, 282 

obesus, fish, 282 
Enteritis, 115, 408, 478 
Entomophobia, 20 
Epeira diadema, spider, 463, 489 
Ephemera vulgata, mayfly, 59, 78, 87 
Ephemeridae, mayflies, 59, 87 
Epimys spp., rats, 353, 360 
Epitheca sp., dragon fly, 59, 87 
Equine biliary fever, 415 

trypanosomiasis, 214 
Erinaceus algirus, hedgehog, 61, 63, 64 
Eristalis spp., flies, 191, 197 

arbustorum, fly, 192, 484 

dimidiatus, fly, 192, 484 

tenax, fly, 115, 192, 477, 484 
Erthesina fullo, bug, 395 
Erysipelas, 95, 108, 115, 479 

Coast, 77 
Erythema urticaria, 404 
Ethmostigmus spinosus, centipede, 465, 488 
Euproctis chrysorrhoea, browntail moth, 

466, 489 
Excitability, caused by insects, 20, 21 
Excreta disposal, 161 

Fannia canicvlaris, lesser house fly, 116, 
117, 135, 136, 139, 142, 143, 144, 192, 
197, 477, 484 
scalaris, latrine fly, 117, 118, 135, 144, 
192, 197, 484 

Farm, insanitary, 35, 36 

Farm sanitation, 36-38 

Fasciol'idae, 260, 261 

Favus, 289, -290, 179 



506 



INDEX 



Febris quintaria, 294 
Fevers, tick, 479 

Field mouse (see Microtus montebelli) 
Filaria bancrofti {nocturna) , human nema- 
tode, 69, 70, 71, 80, 81, 82, 93, 261, 
479 

cypseli, nematode, 72, 86, 91 

demarquaii (see F. demarquayi) 

demarquayi, nematode, 80, 93, 262, 480 

diufna (see Filaria {Loa) loo) 

ephemeridarum, nematode, 78, 87 

gallinarum, fowl nematode, 68, 87, 96, 
486 

geotrupis, nematode, 77, 85 

grassii (see Acanthocheilonema) 

immitis (see Dirofilaria) 

juncea, nematode, 71 

labiato-papillosa (see Setaria) 

loa (see Filaria {Loa) loa) 

{Loa) loa, human nematode, 71, 81, 93, 
95, 220, 480 

martis, rodent nematode, 73, 88 

nocturna (see F. bancrofti) 

ozzardi, nematode, 71 

perstans (see Acanthocheilonema) 

philippinenstis , human nematode, 72, 89 

quadrispina (see F. martis) 

rytipleurites Deslongchamps, nematode, 
62, 91 

rytipletiritis De Magalhaes, nematode, 
78, 88 

sanguinis hominis, nematode, 93 

stomoxeos, nematode, 78, 82 

tucumana, human nematode, 72, 80, 90 
Filariasis, 48, 69, 70, 71, 72, 261, 262 

canine, 261, 479 

human, 220, 478, 480 
Filariidae, 220, 261, 262, 357 
Finch, 259 
Fish, 282 

Five day fever, 294 
Flea abundance, 3b6, 367 

bite treatment, 370, 371, 373 

control, 367-371 

trapping, 369, 370 
Flea-borne diseases, 350-359 
Fleas (see also Aphaniptera), 350-373 
Flesh fly (see Wohlfahrtia magnifica) 
Flies (see Diptera) 

bloodsucking, 208-285 
Flies, non-biting, 105-208 
Flies in Egypt, 450, 451, 452 
Floor maggot (see Auchmeromy\ia luteola) 
Flower vases, 282 
Flukes (see Trematoda) 
Fly attack, avoidance, 203 

baits, 164, 202 

control, 153-174 

paper, 164 

poisons, 202 

repellents, 165 

sprays, 164 

traps, 162, 163, 173, 202 
Folliculitis, 290 



Fontaria virginiensis, myriapod, 54, 55, 88 9 

495 
Food protection, 39, 40, 41, 206 
Foot-and-mouth disease, 180, 480 
Forcipomyia townsendi, midge, 219, 497 

utae, midge, 219, 224, 497 
Forficula auricularia, earwig, 55 
Fountains, drinking, 282 
Fowl (see also chicken), 366 

lice, 339-343 

nematode (see Acuaria spiralis) 

nematode (see Filaria gallinarum) 

tapeworm (see Choanotaenia infundibu- 
lum) 

tapeworm (see Davainea cesticillus) 

tapeworm (see Davainea tetragona) 

tapeworm (see Hymenolepis carioca) 

tick (see Argas persicus) 

trypanosomiasis, 218 
Fox (see also Vulpes vulpes atlantica), 

405 
Frenzy caused by insects, 20, 21 
Frog flukes, 59 
Fumigation, 324, 380 
Funambulus pennatii, palm squirrel, 297, 

475 
Fundulus chrysotus, fish, 282 

diaphanus, fish, 282 

dxspar, fish, 282 

majalis, fish, 282 

notatus, fish, 282 

nottii, fish, 282 

svmilis, fish, 282 
Fungi, 107-115, 209, 210, 211, 249, 289, 

290, 350, 351, 383, 387, 392, 393 
Furunculosis, 290, 411, 480 

Gall sickness, bovine, 218, 480 
Gambusia affinis, top minnow, 282 
Gamocystis tenax, gregarine, 388 
Gangrene, 480 

gas, 109, 115 
Garbage, 37, 39, 40, 41, 160, 202, 282 
Garments, louse-proof, 328 
Gastroenteritis, 115 

Gastrophilus haemorrhoidalis, horse nose 
fly, 183, 190, 196, 205, 484 

intestinalis, horse bot, 182, 183, 184, 185* 
190, 191, 205, 484 

nasalis, horse chin fly, 190, 205, 484 
Gedoelstia spp., flies, 195 
Geophilus carpophagus, centipede, 466, 490 

cephalicus, centipede, 466, 490 

electricus, centipede, 466, 490 

similis, centipede, 465, 466, 488, 490 
Geotrupes douei, beetle, 61, 63, 64, 85, 486 

stercorarius , beetle, 78, 85 
Gerbilhis indicus, jerboa, 296, 474 
Giardia intestinalis; protozoan, 117, 478 
Gigantorhynchidue, 389 
Girostigma spp., flies, 193 
Glanders, 211 

GloMcidium noctuae, owl, 249, 250, 251, 475 
Glomeris limbata, myriapod, 57, 58 



INDEX 



507 



Glossina sp., tsetse fly, 219 

brevipalpis, tsetse fly, 214, 216, 217, 218, 
485, 492, 496 

fusca, tsetse fly, 214, 216, 485, 492 

longipalpis, tsetse fly, 214, 216, 217, 476, 
485, 493, 495 

longipennis, tsetse fly, 214, 216, 474, 492 

morsitam, tsetse fly, 214, 216, 217, 218, 
234, 476, 480, 492, 493, 495, 496 

pallidipes, tsetse fly, 214, 216, 492 

palpalis, tsetse fly, 71, 77, 214, 215, 216, 
217, 218, 220, 234, 476, 480, 492, 493, 
495, 496 

palpalis fuscipes, tsetse fly, 215, 492 

tachinoides, tsetse fly, 214, 216, 217, 218, 
476, 485, 492, 493, 495, 496 
Glossininae, 234. 

Glyciphagus prunorum, mite, 405, 481 
Goat, 373, 405 

lice, 346, 347 

trypanosomiasis, 217 
Goldfish (see Carassius auratus) 
Gongylonema sp., nematode, 78 

brevispicuhvm, nematode, 63, 84, 486 

mucronatum, nematode, 62, 85, 86, 486 

neoplasticum, nematode, 63, 86, 88, 91, 
389, 486 

pulclirwm, nematode, 389, 486 

scutatum, nematode, 62, 84, 86, 88, 95, 
389, 485 
Gonococcus (see Diplococcus gonorrhoeae) 
Gonone, 404, 480 
Gonorrhoea, 108, 115, 291, 480 
Gordiacea, horse-hair worms, 78 
Gordius aquaticus, horse-hair worm, 78 

chilensis, horse-hair worm, 78 

robustus, horse-hair worm, 78 
Gorgodera cygnoides, fluke, 59, 87 

pagenstecheri, fluke, 59, 87 

varsoviensis, fluke, 59, 87 
Gorilla, 373 
Granary beetle (see Tenebrio molitor) 

weeVil (see JSitophilus granarkis) 
Granuloma, equine cutaneous, 480 
Grasshoppers, 78 
Grease-traps, 161 
Gregarina blattarum, gregarine, 388 

legeri, gregarine, 388 
Gregarinida, Gregarinidae, 355, 388 
Ground squirrel (see Citellus beecheyi) 
Grouse, red, haemoproteasis, 213 
Guinea pig, 63, 259 

Gulf Coast tick (see Amblyomma macula- 
turn) 
Gutters, 282 
Gymnoasceae, 289 
Gymnopleurus mopsus, beetle, 63, 85, 486 

sturmi, beetle, 61, 63, 85, 486 

Habronema spp., nematodes, 77, 122 

megastoma, horse nematode, 66, 67, 82, 

121, 486 
microstoma, horse nematode, 66, 67, 78, 

82, 121, 486 



Habronema spp., muscae, horse nematode, 

65, 66, 67, 82, 95, 121, 486 
Habronemic granulomata, 90 
Haemaphysalis spp., ticks, 424 

birmaniae, tick, 417 

bispinosa (see H. birmaniae) 

oinnabarina punctata, tick, 417, 434, 480, 
490 

/lava, tick, 422, 475 

leaclii, tick, 415, 417, 425, 434, 474, 476 

punctata, tick, 425 
Haematobia exigua (see Lyperosia) 

irritans (see Hyperosia) 

sanguisugens, fly, 232 
Haematomyidium spp., flies, 224 
Haematopinus spp., lice, 297, 475 

asikii, horse louse, 347 

eurysternus, cattle louse, 288, 331, 332 

piliferus, dog louse, 344 

suis, hog louse, 344, 345 

vituli, cattle louse, 332 
Haematopota spp., horseflies, 228 

cordigera, horsefly, 220, 480 

duttoni, horsefly, 219 

italica, horsefly, 219 

perturbans, horsefly, 217, 493 

pluvialis, horsefly, 210, 475 

tristiis (see Chrysozona pluviatilis) 

vandenbrandeni, horsefly, 219 
Haematosiphon inodora, bug, 400 
HaematozoOn sp., worm, 92 
Haemo gregarina sp., protozoan, 220 

francae, protozoan, 219 

gracilis, protozoan, 293 

(Jiaemo gregarina) mauritanica, proto- 
zoan, 422, 475 

(Hepatozoon) canis, protozoan, 420, 421, 
424, 474 

{Hepatozoon) funambuli, protozoan, 296, 
475 

{Hepatozoon) gerbilli, protozoan, 296, 
474 

{Hepatozoon) jaculi, protozoon, 355, 422, 
474 

{Hepatozoon) leporis, protozoan, 422, 
475 ^ 

{Hepatozoon) muris, protozoan, 422, 475 

{Karyolysus) lacertarum, protozoan, 422 
Haemogregarinida, Hemogregarinidae 219, 

220, 296, 297, 355, 420, 421, 422 
Haemoproteidae, 212-214, 249 
Haemoproteus columbae, protozoan, 212, 
482 

danilewskyi, protozoan, 249 

mansoni, protozoan, 213, 480 

noctuae, protozoan, 249, 251 

sym'ui, protozoan, 249, 475 
Halarachne americani, mite, 408, 481 

ailc iiu at a, mite, 408, 481 

halicha&ri, mite, 408, 481 
Halipegus ovocaudatus, fluke, 59, 87 
Hallucinations caused by insects, 21 
Haplometra cylindracea, fluke, 59 
HarpyryncJitis longilpilus, mite, 408, 497 



508 



INDEX 



Head louse (see Pediculus humanms) 

Heartwater, 436, 480 

Hedgehog (see also Erinaceus algirus), 417 
nematode (see Gongylonema mucrona- 
tum) 

Helophilus pendulinus, fly, 192, 484 

Hemileuca mala, moth, 467, 489 

Herpestes ichnewmon, mongoose, 62 

Herpetomonas spp. (see Leptomonas) 

Heterandria formosa, fish, 282 

Heterometrus maurus, scorpion, 462, 489 

Heterotricha, 388 

Hide beetles, 454, 455 

Himant allium gervaisi, centipede, 466, 490 

Hippobosca spp., flies, 235 
maculata, fly, 218 
rufipes, fly," 218, 480 

Hippoboscidae, 214, 218, 235, 496 

Hippo centrum trimaculatwm, horsefly, 220, 
480 

Hippopotamus head bot (see Rhinoestrus 
hippopotami) 

Hiss-Werner disease, 294 

Histiogaster entomophagus , mite, 405, 497 
spermaticus, mite, 474 

Hodotermes pretoriensis , termite, 68, 87, 
486 

Hog (see also pig), 389, 408 
louse (see Haematopinns suis) 

Hog- feeding trough, 171, 172 

Holothyrus coccinella, mite, 404, 474 

Homalomyia corvina, fly, 118 

Honey poisoning, 468 

Hookworms (see Ancylostomidae) 

Hoplopsyllus an.om.aUis, flea, 360, 365 

Horse (see also equine), 373, 405, 412 
bot (see Gastrophilus intestinalis) 
chin fly (see Gastrophilus nasalis) 
diseases, 119, 122 

head bot (see Rhinoestrus purpureus) 
lice, 347, 348 

nematode see Gongylonema scutatum) 
nematode (see Habronema megastoma) 
nematode (see Habronema microstoma) 
nematode (see Habronema muscae) 

Horse nose fly (see Gastrophilus haemor- 
rhoidalis) 
sickness, Gambian, 217, 480 
trypanosomiasis, 215, 216, 217 

Horse-hair worms (see Gordiacea) 

Hospitals, 328 

Hot air delousing, 324 

House fly (see Musca domes tica) 

Human flea (see Pulex imitans) 
nematode (see Acanthocheilonema per- 

stans) 
nematode (see Ascaris lumbricoides) 
nematode (see Filaria bancrofti) 
nematode (see Filaria demarquayii) 
nematode (see Filaria (Loa) loa) 
nematode (see Filaria philippinensis) 
nematode (see Filaria tucwmana) 
nematode (see Oncocerca caecutiens) 
nematode (see Oncocerca volvulus) 



Human tapeworm (see Dipylidmm cami- 
num) 
tapeworm (see Hymenolepis diminuta) 
tapeworm (see Hymenolepis nana) 
tapeworm (see Taenia saginata) 
thorn-headed worm (see Macracanthor- 

hynchus hirudinaceus) 
thorn-headed worm (see Moniliformis 
moniliformis ) 
Humidity, 97-104 
Hyalomma aegyptium, tick, 412, 415, 417, 

418, 422, 424, 425, 475, 478, 479, 487 
Hydrocampa nymphaeata (see Nymphula) 
Hydrocyanic acid gas, 325, 326, 380 
Hydrotaea meteorica, fly, 192, 484 
Hygranesthesia, 98, 101 
Hygronochelia, 98, 101 
Hygroplegia, 98, 101 
Hylemyia nidicola, fly, 195 
Hymenolepididae, 120, 356, 357, 389 
Hymenolepis carioca, fowl tapeworm, 57, 
82, 92, 495 
diminuta, rat tapeworm, 42, 53, 54, 55, 

79, 80, 83, 84, 86, 88, 94, 356, 495 
microstoma, mouse tapeworm, 42, 86 
nana, dwarf tapeworm, 53, 55, 56, 79, 80, 
91, 357, 495 
Hypercryalges'ia, 100 
Hyperchiria io, moth, 22 
Hyperthermalgesia, 100 
Hyphomycetes, 289 
Hypoderma bovis, bot, 197, 469, 484 

lineata, bot, 141, 182, 184, 186, 197, 469, 
484 
Hystrichopsylla talpae, flea, 354 



Ilybius fuliginosus, beetle, 59, 85 
Immigrant inspection, 314, 315 
Impetigo contagiosa, 289, 290, 480 

tropical, 289, 290, 481 
Impromptu delousing, 326, 327 
Inactivity, zone of, 98, 99, 101 
Incineration, 158 
Incinerators, 45, 46, 456 
Industrial sanitation, 41, 42 
Inflammation, bronchial, 481 

catarrhal, 481 
Insanity caused by insects, 21 
Insomnia caused by insects, 21 
Insect breeding, 32, 33 

stings, 467, 468 
Insecta, 461 
Intermittent fever, 412 
Isometrus europaeus, scorpion, 462, 489 
Isopoda, sowbugs, 89 
Isoptera, termites, 87 
Itch, bicho-colorado, 403, 481 

chorioptic, 405, 481 

coolie, 405, 481 

copra, 405, 481 

grain, 405 

grocer's, 405, 481 

ground, 405 

guano, 408, 481 



INDEX 



509 



Itch, Norwegian, 405 

psoroptic, 405 

sarcoptic, 405 

Texas, 405 
Ixodes snp., ticks, 424 

bicornis, tick, 409 

(Ceratixodes) putus, tick, 409 

hexagovMS, tick, 416, 425, 476 

holbcyclus, tick, 411, 487 

pilosus, tick, 410, 487 

reduvius (see /. hexagonus) 

ricinus, castor-bean tick, 73, 88, 89, 409, 
411, 417, 425, 434, 476, 487, 480, 490 

Jackal (see Canis aureus), 417 
Jaculus gordoni, jerboa, 355, 422, 474 

orientalis, jerboa, 355, 422, 474 
Janthinosoma lutzi (see Psorophora) 
Japanese river fever, 413 
Jaundice, canine malignant, 415, 416, 417, 
436, 475 

infective or epidemic, 296, 481 
Jerboa (see Dipodillus campestris) 

(see Gerbillus indicus) 

(see Jaculus, spp.) 
Jinja, 250 

Johannsemella spp., midges, 224 
Julus sp., myriapod, 54, 55, 88, 495 

guttulatus, myriapod, 68, 88 

londinensis , myriapod, 466, 490 

terrestris, myriapod, 466, 490 

Kala azar, 262 

Indian, 251, 294, 395, 396, 397, 398, 481 

infantile, 354, 481 
Kara kist (see Theridmm lugubre) 
Katipo (see Latrodectes hasseltii) 
Kedani disease, 413, 481 
Keratitis, phlyctenular, 290 
Kerosene emulsion, 336 
Killifish (see Fundulus spp.) 
Kirkioestrus spp., bots, 195 
Kissing bugs, 469 

Labidesthes sicculus, fish, 282 
Lacerta spp., lizards, 422 
Lachnostema spp. (see Phyllophaga) 
Laelaps echidninus, mite, 422, 475 
Lagoa sp., moth, 22 

crispata, moth, 467, 489 
Lag opus scoticus, red grouse, 214 
Lakes, 276 

Lamblia intestinalis (see Giardia) 
Laminosioptes cysticola, mite, 409, 474 
Lark, 249 

Larvicides, 279, 280 
Lasiocampa pini, moth, 467, 489 
Latrines, 45, 47, 48, 282 
Latrodectes geometricus, spider, 464, 489 

hasseltii, katipo, 464, 489 

mactans, hour-glass spider 463, 489 

scelio (see L. hasseltii) 
Laundry, 319, 320 



Laverania falciparum, plasmodid, 253, 255, 
256, 482 

malariae (see L. falciparum) 
Lecithodendrium ascidia, fluke, 59, 81, 87, 
88 

chilostomum, fluke, 59, 83 
Leiothinae, biru lice, 72, 73, 86 
Leishmania sp., ieptomonid, 395 

brasiliensis, Ieptomonid, 219, 251 

donovani, Ieptomonid, 251, 294, 395-398, 
481 

infantum, Ieptomonid, 354, 481 

tropica, Ieptomonid, 118, 219, 251, 398, 
492 

uta, Ieptomonid, 219, 497 
Leishmaniasis, 482 

oral, 219, 251 
Lepidoptera, moths, 59, 83 
Lepidopterous larva poisoning, 466 
Lepomis cyanellus, fish, 282 

gibbosus, fish, 282 
Leprosy, 112, 115, 392, 481, 482 
Leptomonas sp., Ieptomonid, 354 

algeriense, Ieptomonid, 251 

blattarwm, Ieptomonid, 388 

calliphorae, Ieptomonid, 117 

ctenocephali, Ieptomonid, 354 

ctenophthalmi, Ieptomonid, 355 

ctenopsyllae, Ieptomonid, 355 

culiois, Ieptomonid, 252 

debreuili, Ieptomonid, 355 

drosophilae, Ieptomonid, 117 

homalomyiae, Ieptomonid, 117 

lineata, Ieptomonid, 117 

luciliae Roubaud, Ieptomonid, 117 . 

luoiliae Strickland, Ieptomonid, 117 

mesnili, Ieptomonid, 117 

minuta, Ieptomonid, 219 

muscae-domesticae, Ieptomonid, 117 

pattoni, Ieptomonid, 355 

pediculi, Ieptomonid, 294 

phlebotomi, Ieptomonid, 219 

pycnosomae, Ieptomonid, 118 

rpubaudi, Ieptomonid, 118 

sarcophagae, Ieptomonid 118 

simuliae, Ieptomonid, 219 

soudanensis , Ieptomonid, 118 

stratiomyiae, Ieptomonid, 118 

subulata, Ieptomonid, 219 
Leptomonidae, 117, 118, 219, 251, 252, 294, 

354, 355, 388, 395-398, 414-418 
Leptopsylla musculi, flea, 351, 488 
Leptospira* hebdomadis, spirochaete, 413 

icterohaemorrhagiae, spirochaete, 296, 
481 

icteroides, spirochaete, 259, 260, 497 
Leptus akamushi, mite, 404, 413, 477, 497 

americanus, mite, 404, 477 

irritans, mite, 404, 477 
Lepus spp., rabbits, 353 

nigricollis, rabbit, 422, 475 
Leucocytozoidae, 214, 250 
Leucocytozoon dcenilewskyi, protozoan, 250. 
251, 475 



510 



INDEX 



Leucocytozoon lovati, protozoan, 214 
Leucophaea sp., cockroach, 376 
L&wisonella spp. (see Trypanozoon) 
Lice, 286-348 

animal, 330-348 

in Egypt, 452 
Life zones of temperature and humidity, 

98-104 
Limnophilus flavicornis, caddice fly, 59, 

83 

griseus, caddice fly, 59, 83 

lunatus, caddice fly, 59, 83 

rhombicus, caddice fly, 59, 83 
Lvmosina punctipennis (see Borborus) 
Linognathus pedalis, sheep foot louse, 345 

stenopsis, goat louse, 346, 347 

vituli, cattle louse, 288 
Linseed oil for cattle lice, 334, 335 
Lion, 373, 405 

Liponyssus bacoti, mite, 404, 474 
Lipoptena cervi, fly, 235 
Lithobius forficatus, centipede, 466, 490 

melanops, centipede, 466, 490 
Living quarters, 327 
Lizards, 226 
Llama, 405 
Loasis, 482 
Lone Star tick (see Amblyomma ameri- 

canum) 
Lbschia coli,, amoebid, 116 

histolytica, amoebid, 117, 478 
Louse, body (see Pedicuhis corporis) 

crab (see Phthirus pubis) 

control, 312-329 

head (see Pedicuhis humarms) 

ravages, 312, 313 
Louse reservoirs, 313, 314 
Louse borne diseases, 286-297 
Louse-ulcers, 287 
Lucania parva, fish, 282 

venusta, fish, 282 
Lucilia spp., flies, 117, 118 

argyrocephala, fly, 180, 485 

caesar, green bottle fly, 105, 108, 109, 
110, 111, 112, 113, 114, 132, 133, 140, 
177, 179, 180, 181, 453, 475, 477, 485, 
492 

nobilis, fly, 149 

serenissima, fly, 117, 118, 180, 480, 485 

sericata, green bottle fly, 131, 132, 140, 
143, 148, 149, 177, 179, 180, 181, 453, 
485 

sylvarum, fly, 132 

tasmaniensis , fly, 181, 485 
Lungs, inflammation of, 408 
Lycosa narbonensis, spider, 463, 489 

tarantula, spider, 463, 489 
Lymantria. monacha, moth, 467, 489 
Lymphangitis, 69, 409 

epizootic, 411, 482 
Lymph-scrotum, 69 
Lynchia spp., flies, 235 

brunea, fly, 212, 482 

maura, fly, 212, 213, 219, 482 



Lyperosia sp., fly, 214, 218 

exigua, horn fly, 215, 232, 494 

irritans, horn fly, 169, 210, 232, 233, 234, 

475 
rndnuta, fly, 215, 494 

Macracanthorhynchus hirudinaceus , thorn- 
headed worm, 79, 85, 86, 495 
Macrothylacia rubi, moth, 467, 489 
Maculae coeruleae, 288, 482 
Mai de caderas, 393, 482 
Malacotylea, 120, 121 
Malaria, 48, 262 

aestivo-autumnal, 253, 255, 256 

avian, 259, 482 

canary, 482 

malignant tertian, 253, 255, 256 

pernicious, 252 

pigeon, 212, 213, 482 

quartan, 253, 256, 257, 482 

subtertian, 253, 255, 256, 482, 483 

tertian, 253, 257, 258, 259, 483 

unclassified, 253, 254, 255, 482 
Malassezia spp., fungi, 289, 487 
Mallophaga, biting lice, 86 
Mange, 405 

demodectic, 407, 484 

pscroptie, 484 
Mansonia sp., mosquito, 250, 485 

pseudotillans, mosquito, 262, 480 
Mansomioiitdes africanus, mosquito, 261, 
262, 479 

armulipes, mosquito, 70, 82, 262, 480 

uwiformis, mosquito, 70, 82, 250, 262, 479 
Manure, 153-160 

bin, 157 

broadcasting, 156 

clean-up, 158 

collection, 156 

hog, 172, 173 

incineration, 158 

inspection, 158, 160 

loading platforms, 156,. 158 

piles, 159 

scraper, 159 

shipment, 158 

spreader, 157 
Margaropus winthemi, tick, 410 
Marmoset (see Midas spp.) 
Mastigophora, 117-119, 212-219, 249-260, 
294-296, 352-355, 388, 393-399, 414-420 
Mastophorus echiurus, nematode, 78, 86 

globocaudatus, nematode, 78, 85 
Mayflies (see Plectoptera) 
Mbori, 228, 251, 484 
Meal moth (see Asopia farinalis) 
Measles, 116, 122, 484 
Mediterarnean Coast Fever of cattle, 415, 

484 
Megalopyge opercularis, moth, 467, 489 
Melanodermia, 287, 288, 484 
Melanolestes p icipes, kissing bug, 469, 489 
Melipona spp., bees, 489 
Meloidne, 469, 478 



INDEX 



511 



Melolontha melolontha, June beetle, 79, 85, 
495 

vulgaris (see Melolontha melolontha) 
Melophagus ovirms, sheep tick, 212, 219, 

235, 346 
Meningitis, cerebrospinal, 108, 115, 289, 

290, 484 
Meningococcus sp., microorganism, 289 
Mercurial ointment, 337 
Meriones spp., rodents, 353 
Mermithidae, 78, 262 
Mesogoniatus chaetodon, fish, 282 
Metatrombidiwm poriceps, mite, 404, 477 
Metazoa, 220, 260, 297, 355, 389, 390 
Miana tick fever, 484 
Mice, 355, 395 

white, 393 
Micro calliphora domestica, fly, 485 

varipes, fly, 181, 485 
Micrococcus sp., microorganism, 292 

flavus, microorganism, 108 

melitensis, microorganism, 248 

nigrofasciens, microorganism, 383 

tetragenus, microorganism, 108 
Microfilaria diurna (see Filaria (Loa) 
loa) 

perstans (see Acanthocheilonema) 
Microneurum fumcola, fly, 109, 477 
Microtrombidium pusillum, mite, 404, 477 

tlalsahuate, mite, 404, 477 

wichmanni, mite, 404, 480 
Microtus spp., mice, 352 

montebelli, field mouse, 413 
Midas geoffroyi, marmoset, 259 

oedipus, marmoset, 259 
Midges (see Chironomidae) 
Milk bacteria, 112, 115 
Minnow, top (see Gambusia afflnis) 
Mites, 403-429 

Mollienisia latipinna, fish, 282 
Mongoose (see Herpestes ichneumon) 
Moniliformis moniliformis, thorn-headed 

worm, 79, 84, 88, 389, 495 
Monkey, 291, 408 

(see Ateles pentadactylus) 

(see Cynomolgus cynocephalus) 
Morbus errorum, 287 
Mosquito control, 275-285 

repellents, 284 

sources, 276 

stains, 276 

traps, 283 
Mosquitoes, 69, 70, 71, 247-285 
Mouse, 408 

nematode (see Protospirura muris) 

tapeworm (see Hymenolepis diminuta) 

tapeworm (see- Hymenolepis microstoma) 

tapeworm (see Hymenolepis nana) 
Municipal boarding houses, 41 
Murrina, 119, 122, 484 
Mus spp., mice, 352, 353 

musculus, mouse, 118, 294 
Musca sp., fly, 118 

bezzii, fly, 229 



Musca sp., convexifrons, fly, 229 
corvina, fly, 229 

domestica, house fly, Frontispiece, 56, 57, 
65, 66, 67, 68, 82, 105, 106, 108, 109, 
111, 112, 113, 114, 116, 117, 118, 119, 
120, 121, 122, 127-130, 139, 140, 142, 
144, 145, 151, 180, 477, 478, 479, 480, 
481, 484, 486, 487, 488, 489, 492, 494, 
495, 497 
gibsoni, fly, 229 
nebulo, fly, 118, 121, 487 
nigrithorax, fly, 229 
pattoni, fly, 229 
Muscidae, 228-234 
Muscina assimilis, fly, 453 

stabulans, non-biting stable fly, 135, 136, 
140, 143, 146, 147, 180, 192, 453, 484, 
485 
Mustela foina, weasel, 73 
Mycterotypus bezzii, fly, 224 

irritans, fly, 224 
Mydaea anomalu, fly, 188, 485 
pici, fly, 195, 484 
spermophilae, fly, 188 
torquens, fly, 188, 485 
vomiturationis, fly, 192, 484 
Myiasis, 22, 175-208 
auricular, 180 

bloodsucking larvae, 195, 196, 484 
classification, 175, 176 
head passage, 193-195, 484 
intestinal, 190-193, 484 
ocular, 180 

prevention and treatment, 200-208 
subdermal, 175, 182-190, 484 
tissue destroying, 175, 176-181, 485 
urogenital, 190, 193, 484 
Myobia musculi, mite, 408, 497 
Myoxus spp., rodents, 352, 353 
Myriapoda, millipedes, centipedes, 88 
Mystacides nigra, caddice fly, 59, 83 
Myxococcidium stegomyiae, microorganism, 

249 
Myxosporidia, 120, 388 

Nagana, 214, 228, 230, 250, 393, 485 

Nasal myiasis, treatment, 204 

Nausea, caused by 'insects, 21 

N.C.I, powder 

Necator americanus, hookworm, 122, 480 

Nemathelminthes, 121, 122, 220, 261-263, 

357, 389 
Nematoda, nematodes, 59-78, 88, 121, 122, 

220, 261-263, 357, 389, 390 
Nematode, bovine, 484 

canine, 486 

donkey, 486 

dromedary, 486 

equine, 486 

fowl, 486 

fox, 486 

hedgehog, 486 

hog, 486 

jerboa, 486 



512 



INDEX 



Nematode, mongoose, 486 

rodent, 486, 487 
Neocuterebra squamosa, bot, 190, 485 
Neopollenia stygia, fly, 181, 485 
Neosporidia, 121, 388 

Nephrophages sanguinarius , mite, 408, 474 
Nervous exhaustion, caused by insects, 20, 

21 
Neuroctena anilis, fly, 118 
Neuroptera, 59, 82 
Nicotin wash, 337 

Nigua (see DermatophiVus penetrans) 
Nochelic subzone, 98, 102 
Nose protection, 205 
Nosema apis, protozoan, 120 
Nosemidae, 120 

Notemigonus crysoleucas, fish, 282 
Notidobia oiliaris, caddice fly, 59, 83 
Notoedres cati cati, mite, 405, 491 

muris, mite, 491 
Nuttallia spp., piroplasmid, 414 

equi, piroplasmid, 417, 436, 487 
Nuttalliosis, equine, 417, 487 
Nycteribiidae, 235 
Nyctotherus ovalis, ciliate, 388 
Nymphula nymphaeata, moth, 59, 83 

Octosporea monospora, protozoan, 120 
Ocular acariasis, 487 
Odonata, dragon flies, 59, 87 
Oedemagena tarandi, reindeer bot, 188, 

485 
Oestrus ovis, sheep bot, 176, 193, 198, 207, 

469, 484 
Oilers, 281 
Oiling, 280 

Oils for treating cattle, 334, 335 
Olethric zone, 98, 102 
Oligoneuria rhenana, mayfly, 78, 87 
Oncocerca sp., cattle nematode, 77 

caecutiens, nematode, 77 

lienalis, cattle nematode, 77 

volvulus, human nematode, 77 
Onitis irroratus (see Chironitis) 
Onthophagus spp., beetle, 62, 64, 85, 486 

bedeli, beetle, 63, 64, 85, 486 

hecate, beetle, 62, 86, 485 

nebulosus, beetle, 64, 86, 486 

pennsylvanicus, beetle, 62, 86, 485 
Ophthalmia, purulent, 116, 122, 487 

nodosa, 466, 487 
Ophyra spp., flies, 453 

nigra, fly, 181, 485 
Opisthioglyphe rastellus, fluke, 59, 83, 87 
Optimum temperature, 100 
Organisms carried by insects, 27, 28, 29 
Ornithodoros spp., ticks, 423, 424 

coriaceus, tick, 4C9, 487 

megwini, tick, 408, 420, 424, 426, 431, 
433, 434, 444, 445, 487, 490 

moubata, African relapsing fever tick, 
72, 74, 75, 89, 96, 414, 418, 419, 420, 
423, 424, 432, 433, 448, 476, 479, 490, 
491, 493 



Ornithodoros spp., savignyi, tick, 412, 
418, 423, 424, 434, 479, 490 

turicata, tick, 409, 420 
Ornithomyia spp., flies, 235 

lagopodis, fly, 213, 214, 480 
Orthoptera, 88 

Oscmiis pallipes, gnat, 119, 497 
Otoacariasis, 408, 487 
Otodectes cynotis, mite, 408, 487 
Otomyiasis, 149 
Ovine trypanosomiasis, 218 
Owls, 249 

Oxyuridae, 121, 389, 390 
Oxyuris blattaeorientalis, worm, 389 

bulhoesi, worm, 389 

curvula, worm, 121, 487 

diesingi, worm, 389 

kunckeli, worm, 389 

vermicular is, worm, 121 



Packing house insects, 40, 453-460 
Paederus cohimbinais, beetle, 469, 478 
Pahvant Valley plague, 209 
Palm squirrel (see Funambulus pen- 

natii) 
Panama larvicide, 280 
Pangonia spp., horseflies, 228 
Panoplites sp., mosquito, 75, 82, 479 

africanus (see Mansonioides) 
Pappataci fever, 49, 211, 226, 487 

flies (see Phlebotomus spp.) 
Parachordodes pustulosus, horse-hair worm, 
79 

tolusawus, horse-hair worm, 79 

violaceus, horse-hair worm, 79 
Paracolitis, 487 

Paragordms tricuspidatus, horse-hair worm, 
79 

varims, horse-hair worm, 78, 79 
Paralysis, Australian human tick, 411 

infantile (see also Poliomyelitis), 116, 
487 

insect, 22 

North American human tick, 409, 410 

South African tick, 410 

tick, 487 
Paraplasma flavigenwn, protozoan, 259 
Paratyphoid A fever, 112, 115, 487 

B fever, 112, 115, 487 
Partridge, 259 

Passer domesticus, English sparrow, 252 
Passeromyia heterochaeta, fly, 196, 484 
Pasture rotation, 441 
Paunch manure, 456 
Pecilothermal, 101 
Pediculoides ventricosus, mite, 404, 405, 

497 
Pediculosis, 22 

capitis, 286, 287 

corporis, 286, 287 
Pediculus spp., lice, 481 

capitis (see P. humawms) 

consobrinus, monkey louse, 302 



INDEX 



513 



Pedicuhis spp., corporis, body louse, 286, 
289, 290, 291, 292, 293, 294, 296, 301, 
302, 304, 305, 306, 307, 308, 309, 310, 
317-28, 478, 479, 481, 484, 487, 488, 490, 
491, 495, 497 
humanus, head louse, 286, 289, 290, 294, 
295, 301, 302, 306, 316, 317, 477, 480, 
482, 488, 497 
vestimenti (see P. corporis) 
Pellagra, 212, 225, 230, 487 
Periplaneta sp., cockroach, 375 

americana, 63, 78, 79, 88, 376, 378, 379, 

383, 387, 388, 389, 477, 486, 495 
amtralasiae, 376, 380 
Peritonitis, 408, 487 
Perlidae, stoneflies, 59 
Personal prophylaxis, 315 
Pharyngobolus africanus, bot, 193, 484 
Phidippus audax, spider, 463, 489 
Philaemato-myia eras sir ostris, fly, 215, 494 

•insignis, fly, 229 
Philaematomyinae, 229 
Phlebotomus fever, 211 
minutus, fly, 219, 226, 492 
minutus africanus, fly, 219 
papatasii, pappataci fly, 211, 226, 487 
verrucarum, fly, 211, 226, 497 
Phormia azurea, fly, 195, 484 
metallica, fly, 195 
regina, black blowfly, 132, 133, 135, 141, 

177, 178, 179, 453, 485 
sordida, fly, 195, 484 
Phosohorus, 382 
Phryganea sp., caddice fly, 59, 83 

grandis, caddice fly, 59, 83 
Phthiriasis, 286, 287, 288 
Phthirus inguinalis (see P. pubis) 

pubis, crab louse, 286, 301, 302, 316, 475, 
476, 482, 484, 495 
Phyllophaga arcuata, June beetle, 79, 86, 

495 
Phyllostomus sp. (bat), 251 
Physocephalus sexalatus, nematode, 64, 65, 

78, 85, 86, 95, 486 
Pig (see also hog), 373, 405 
nematode (see Arduenna strongylijia) 
nematode (see Physocephalus sexalatus) 
pens and pig lots, 170, 171, 172, 173 
thorn-headed worm (see Macracantho- 
rhynchus hirudinaceus) 
Pigeon lice, 343 
Pin itch, 122 
Pink eye, 109 
Pinworm, equine, 487 

Pinworms (see Oxyuridae), 121, 389, 390 
Piophila casei, cheese maggot, 192, 454, 

484 
Piroplasma spp., protozoa, 414 
bigeminum (see Babesia) 
hominis, protozoan, 413 
Piroplasmidae, 414 
Piroplasmosis, 487 
Pityriasis, 289, 290, 487 
Plague, 49 



Plague, bubonic, 112, 115, 350, 351, 360, 
365, 392, 393, 488 

rodent, 114, 115, 209, 230, 351, 488 
Planorbis exustus, snail, 260 
Plasmodidae, 252, 259 

Plasmodium sp., malaria organism, 252, 
483 

danilewskyi, malaria organism, 259, 482 

falciparum (see Laverania) 

malariae, malaria organism, 253, 257, 482 

relictum, malaria organism, 259, 482 

vivax, malaria organism, 253, 257, 258, 
259, 483 
Platyhelmia, 120, 121, 260, 261, 355, 356, 

357, 389 
Plecoptera, stoneflies, 59, 88 
Plectoptera, mayflies, 59, 87 
Pleurogenes claviger, fluke, 59, 86 

medians, fluke, 59, 86, 87 
Plica polonica, 287, 488 
Plistophora sp., protozoan, 388 

periplaneta, protozoan, 388 
Pneumococcus septicaemia, 289, 290 
Pneumonoeces similis, fluke, 59, 87 
Pneumonyssus simicola, mite, 408, 481 
Pogonomyrmex barbatus, ant, 468, 488 

calif ornicus, ant, 468 
Poisoning, bee, wasp and ant, 488 

bug, 488 

centipede, 464-466, 488 

food, 111, 114, 115, 489 

honey, 468, 489 

insect, 21, 22, 461-471 

kissing bug, 489 

lepidopterous larvae, 466, 489 

scorpion, 461-463, 489 

spider, 463, 464, 489 
Poliomyelitis, 116, 122, 211, 212, 230, 248, 

249, 393, 489 
Polistes spp., wasps, 468, 488 
Pollenia rudis, fly, 118, 192, 484 

villosa (see Neopollenia sty g id) 
Polydesmus complanatus, centipede, 466, 

490 
Polymastigidae, 117 
Polymastigina, 117, 388 
Polyneuritis, 291 

Polyplax spinulosus, rat louse, 294, 296, 
491, 496 

stephensi, jerboa louse, 296, 474 
Porcellio laevis, sowbug, 68, 89, 486 
Porrigo, 289, 490 
Porthesia similis, moth, 467, 489 
Porthetria dispar, gipsy moth, 467, 489 
Pot-holes, 277 

Practicotatum,. 98, 100, 101, 102 
Priesz-Nocard organism, 411, 482 
Prionurus amoureuni, spider, 462, 489 

oitrinus, spider, 462, 489 
Prisoners, inspection, 41 
Privies, 37, 39 

Prosotocus confusns, fluke, 59, 86, 87 
Protection of body against mosquitoes, 
283, 284 



514 



INDEX 



Protomonadina, 117 

Protospirura rrmris, rodent nematode, 60, 

78, 80, 86, 93, 357, 487 
Protozoa, 116-120, 212-220, 249-260, 294- 

297, 352-355, 388, 393-399, 414-423 
Prowazekia sp., protozoan, 117 
Prurigo senilis, 287 
Pruritis, 287, 288, 409 
Pseudoedema, malignant, 386, 490 
Pseudoparasitism of nasal passages, etc., 

490 
Pseudopyrellia corwicina, fly, 136, 169 
Psorergates simplex m/usculvrms, mite, 408, 

497 
Psorophora lutzi, mosquito, 188 

sayi, mosquito, 249, 475 
Psoroptes communis bovis, mite, 405, 484 

cuniculi, 408, 487 

equi, mite, 405, 484 

ovis, mite, 405, 484 
Psychodidae, 226, 228 
Ptinus spp., beetles, 475 
Pulex brasiliensis , flea, 352, 496 

irritans, human flea, 53, 54, 55. 76, 80, 
351, 352, 354, 355, 356, 357, 360, 362, 
363, 479, 481, 488, 494, 495, 496 
Pupipara, 235 
Pus, green, 113, 115 
Pustular dermatitis, 287 
Pycnosoma bezziana, fly, 180, 485 

chloropyga, fly, 485 

flaviceps, fly, 180, 485 

marginale, fly, 180, 485 

megacephala, fly, 180, 485 

putorium, fly, 118, 180, 485 

rufi fades (see Chrysomya) 
Pygiopsylla ahalae, flea, 351, 365, 488 
Pyodermia, 287, 288, 490 
Pyrethrum powder, 381, 382 

Rabbit, 63 
fleas, 353 
lice, 343, 344 

Rain barrels, 282 

Rat (see also rodent), 389, 395, 404, 422 
fleas, 350, 351 

louse (see Polyplax spinulosa) 
nematode (see Gongylonema neoplasti- 

cum) 
nematode (see Protospirura inuris) 
tapeworm (see Hymenolepis diminuta) 
tapeworm (see Hymenolepis nana) 
thorn-headed worm (see Moniliformis 
moniliformis) 

Rat-tail maggots (see Eristalis spp.) 

Raven, 249 

Red bug, 404 

grouse (see Lagopus scoticus) 

Reduviidae, 399 

Redwater, 414 
British, 417, 490 

Reindeer bot (see Cephenomyia trompe) 
(see Oedemagena tarandi) 

Relapsing fever, 48, 403 



Relapsing fever, Abyssinian, 418, 490 

American, 420, 490 

Asiatic, 295, 490 

East African, 420, 490 

European, 296, 313, 398, 399, 420, 491 

Manchurian, 296 

North African, 295, 296, 398, 491 

Tropical African, 296, 398, 418, 491 
Rhiganesthesia, 98 
Rnigonochelia, 98, 100 
Rhigoplegia, 98, 101 
Rhinoceros bots, 193 
Rhznoestrus hippopotami, bot, 195, 484 

nasalis, bot, 194, 484 

purpureus, bot, 194, 198, 207, 484 
Rhipicephalus spp., ticks, 424, 435 

appendiculata, tick, 417, 425, 436, 447, 
478 

bursa, tick, 417, 436, 476 

capensis, tick, 415, 417 

evertsi, tick, 417, 420, 424, 425, 436, 478, 
487, 493 

sanguineus, tick, 74, 76, 89, 414, 415, 420, 
421, 424, 425, 436, 474, 476 

siculus, tick, 410, 414, 417, 425, 474, 476, 
478, 487 
Rhizoglyphus parasiticus, mite, 405, 408, 

481, 487 
Rhodesian fever, 417, 491 
Rhodnius prolixus, bug, 394, 476 
Rhyacophila nubila, caddice fly, 59, 83 
Rhynchoidomonas luciliae, protozoan, 118 
Rhyzoglyphus parasiticus (see Rhizogly- 
phus) 
Rickettsia melophagi, microorganism, 212 

pediculi, microorganism, 292, 294, 497 

prowazeki, microorganism, 292, 497 

quintana, microorganism, 293, 495 
Robin, 195 

Rocky Mountain spotted fever, 403, 412, 
491 

tick (see Dermacentor andersoni) 
Rodent trypanosomiasis, 294 
Rossiella spp., protozoa, 414 

rossi, protozoan, 417, 474 

Sanitation, entomological, 34-42 
Sarcina alba, microorganism, 383 

aurantiaca, microorganism, 108, 384 

lutea, microorganism, 384 
Sarcodina, 116, 117, 388 
Sarcophaga spp., flies, 119, 453, 484, 497 

aurifrons, fly, 181, 485 

camaria, fly, 105, 108, 109, 110, 111, 112, 
113, 114, 180, 475, 477, 485, 492 

haemorrhoidalis, fly, 118, 180, 191, 484, 
485 

lamb ens, fly, 179, 485 

murus, fly, 118 

pyophila, fly, 179, 197, 485 

regularis, fly, 180, 485 

robusta, fly, 135 

ruficornis, fly, 180 

saraceniae, fly, 117, 132, 136 



INDEX 



515 



Sarcophaga spp., texama, fly, 132. 

tuberosa sarracenioides, fly, 132 
Sarcophagidae, 141, 144, 150, 151, 177 
Sarcoptes aucheniae, mite, 405, 491 

bovis, mite, 405, 491 

canis, mite, 405, 491 

caprae, mite, 405, 491 

dromedarii, mite, 405, 491 

equi, mite, 405, 491 

leomis, mite, 405, 491 

ovis, mite, 405, 491 

scabiei crustosae, mite, 405, 491 

scabiei hominis, mite, 405, 491 

suis, mite, 405, 491 

vulpis, mite, 405, 491 
Sarcoptidae, 405 
Sawdust, oil-soaked, 281 
Scab, 491 

sheep, 405 
Scabies, 48, 405, 491 
Scaly leg, 405, 406, 407, 492 
Scarabaeus (Ateuchetus) variolosus, beetle, 
61, 64, 86, 486 

(Ateuchus) sacer, beetle, 61, 63, 64, 65, 
86, 486 
Scarlet fever, 116, 122, 492 
Scatophaga lutaria, fly, 118 
Scaurus striatus, beetle, 42, 54, 86, 495 
Schistosoma mansoni, worm, 120, 121 
Schistosomiasis, 120 
Schistosomidae, 120, 121 
Schizomycetes, 107-115, 209-211, 249, 289, 

290, 350, 351 
Schizotrypanum cruzi, trypanosome, 393, 

394, 395, 414, 475 
Scholeciasis, 22 

Schongastia vandersandei, mite, 404, 480 
School children, inspection, 40 
Scolopendra cingnlata, centipede, 465, 488 

gigantea, centipede, 465, 488 

heros, centipede. 465, 488 

morsitans, 'centipede, 465, 488 
Scops gin, owl, 249 
Scorpion poisoning, 461-463 
Scorpionidea, 461 
Scouting for mosquitoes, 275 
Screening, 162, 206, 283 

of food, 39 

of houses, 36 
Screw worms (see Chrysomya macellaria) 
Scutigera coleoptrata, centipede, 466, 

490 
Scutomyia albolineata, fly, 70, 80, 262, 480 
Sebaceous tumor, 408 
Seborrhea, 407, 492 
Seepage water, 277 
Sense organ injury, 21 
Septicaemia, 108, 110, 111, 115, 211, 230, 

289, 290, 411, 492 
Serbian barrel disinfector, 322 
Setaria labiato-papillosa, cattle nematode, 

77, 82, 94 
Seven-day fever, 413 
Sewage, 40, 41, 161 



Sewers, 282 
Sheep, 373, 405, 410 

bot (see Oestrus ovis) 

lice, 345, 346 
Sheep maggots, 181 

nematode (see Gongylonema scutaturn) 

tick (see Melophagus ovinus) 
Shrew tapeworm, 57 
Sialis lutaria, dobson fly, 59, 82 
Sibine stimulea, moth, 467, 489 
Simian trypanosomiasis, 218 
Simuliidae, 224, 225, 226 
Simulium spp., buffalo gnats, 212, 224, 
225, 226, 487 

bract eatum, buffalo gnats, 227 

columbaczense, buffalo gnats, 219 

dkielli, buffalo gnats, 77 

jenningsi, buffalo gnats, 227 

pictipes, buffalo gnats, 227 

samboni, buffalo gnats, 77 

venustum, buffalo gnats, 227 

vittatum, buffalo gnats, 227 
Siphonaptera (see Aphaniptera) 
Sitophilus granarius, beetle, 42 
Sleeping sickness, 262 

Gambian, 215, 230, 250, 492 

Nigerian, 215, 492 

Rhodesian, 217, 250, 492 
Smallpox, 116, 122, 291, 492 
Soaps, 318 

Sodium fluoride, 341, 342, 343, 381 
Sore, Bagdad, 118, 219, 226, 492 

Biskra, 219, 492 

Cambay, 118 

non-ulcerating oriental, 395 

Oriental, 118, 251, 398, 492 

tropical, 262 
Souma, 217, 228, 230, 493 

Zambian, 217, 493 
Sowbug (see Porcellio laevis) 
Sparrow, 249, 259 
Spider poisoning, 463, 464 
Spilopsyllus leporis, flea, 353, 496 
Spinose ear tick (see Ornithodoros meg- 

nini) 
Spirillaceae, 115, 387 

Spirillum (Vibrio) cholerae, microorgan- 
ism, 115, 387, 477 

metchnikovi, microorganism, 387, 

478 
Spirocerca sanguino lenta. dog nematode 

60, 65, 84, 85, 86, 88, 91, 486 
Spirochaeta gaUica, spirochaete, 293 
Spirochaetacea, 219, 259, 260, £95, 296, 355, 

398, 418-420 
Spirochaetidae, 119, 219, 259, 260, 295-296, 

355, 398, 418-420. 
Spirochaetosis, 49 

boVine, 420, 493 

goose, 418, 494 

North American fowl, 493 

Senegal fowl, 420, 493 

South American fowl, 193 

Sudanese fowl, 119 



516 



INDEX 



Spiroptera obtusa (see Protospirura muris) 
(Filaria) sanguinolenta (see Spirocerca) 
(Gongylonema) neoplasticum (see Gon- 
gylonema) 
Spiroschaudinnia spp., spirochaetes, 296, 
418, 490 
anserina, spirochaete, 418, 494 
berbera, spirochaete, 295, 398, 491 
carteri, spirochaete, 295, 490 
ctenocephali, spirochaete, 355 
culicis, spirochaete, 259 
duttoni, spirochaete, 296, 398, 491 
duttoni, Brumpt, spirochaete, 418 
duttoni, Novy and Knapp, spirochaete, 

418, 419 
exanthematotyphi, spirochaete, 292 
glossinae, spirochaete, 219 
granulata, spirochaete, 419, 493 
marchouxi, spirochaete, 493 
neveuxii, spirochaete, 420, 493 
novyi, spirochaete, 420, 490 
recurrentis, spirochaete, 295, 296, 398, 

420, 491 
rossii, spirochaete, 420, 490 
theileri, spirochaete, 420, 493 
Spirura gastrophila, cat nematode, 60, 61, 

84, 85, 95, 389, 486 
Spiruridae, 121, 357, 389 
Splenic fever, 414, 494 
Sponge baths, 318 
Sprays for cattle, 335, 336 
Squirrel, 355, 409 

bot, 187 
Stable fly (see Stomoxys calcitrans) 
Stables, 39, 40 
Staphylinidae, 469, 478 
Staphylococcus spp., microorganisms, 482 
pyogenes, microorganisms, 411, 480 
pyogenes albus, microorganisms, 108, 210, 

289, 384, 480, 492 
pyogenes aureus, microorganisms, 108, 

210, 289, 384, 480, 492 
pyogenes citreus, microorganisms, 108, 
492 
Steam, enclosed, 322, 323 
live, 322 

sterilization, 321-323 
Stegomyia calopus (see Aedes argenteus) 
fasciata (see Aedes argenteus) 
gracilis (see Aedes) 
ingens, mosquito, 251 
Sterilization, steam, 321-323. 
Sternostomum rhinolethrum, mite, 408, 481 
Stigmatogaster subterraneus, centipede, 

466, 490 
Stomoxydinae, 229, 230, 232, 233 
Stomoxys spp., flies, 217, 218 

calcitrans, stable fly, 57, 66, 67, 77, 78, 
82, 126, 139, 140, 143, 145, 146, 209, 
210, 211, 212, 214, 215, 216, 217, 220, 
221, 230, 231, 232, 474, 475, 476, 477, 
478, 485, 487, 488, 492, 493, 494, 495 
geniculatus, fly, 215 
glauca, fly, 214, 485 



Stomoxys spp., nigra, fly, 215, 216, 217, 220, 

476, 493, 494 
Stoneflies (see Plecoptera) 
Stratiomyia chameleon, fly, 118 

potamida, fly, 118 
Straw, 231, 232 
Streams, clearing, 276 
Streblidae, 235 
Streptococcus sp., microorganism, 211, 492 

equiwus, microorganism, 107 

fecalis, microorganism, 108 

pyogenes, microorganism, 108, 479 

salivarius, microorganism, 108 
Strickeria jiirgensi, protozoan, 292 
Strix flam.7F.9a, owl, 249 
Submarine saws, 277 
Submersible automatic oil bubbler, 281 
Sulphur flowers, 343, 382 

fumigation, 381 

gas, 324, 325 
Suppurating wounds, 113, 494 
Suppuration, 108 

Surra, 119, 122, 215, 228, 230, 250, 494 
Swamp fever, 211 
Swamps, 276 

Swift (see Cypselus offinis) 
Swine (see hog) 
Syphilis, 291 

Syrnium aluco, owl, 249, 250, 475 
Syrup factories, 41 

Tabanidae, 211, 214, 218, 219, 228, 236- 

246, 251, 496 
Tabanus spp., horseflies, 210, 214, 217, 219, 

228, 485, 492 
atratus, horsefly, 210, 215, 475 
biguttatus, horsefly, 215, 217, 484, 493 
bovinus, horsefly, 210, 475 
chrysurus, horsefly, 211, 474 
corax, horsefly, 239, 240 
ditaeniatus, horsefly, 237, 242, 243, 246 
fasciatus, horsefly, 220 
fumifer, horsefly, 215, 494 
hilaris, horsefly, 219 
kingi, horsefly, 237, 240, 242, 246 
lasiophthalmus , horsefly, 243, 244 
lineola, horsefly, 215, 494 
minimus, horsefly, 215, 494 
par, horsefly, 220, 237, 240, 242 
partitus, horsefly, 215, 494 
phaenops, horsefly, 236, 237, 239, 240, 

241, 242, 243, 245 

punctifer, horsefly, 236, 237, 238, 239, 

240, 241, 243, 245 
secedens, horsefly, 220 
socialis, horsefly, 220 
striatus, horsefly, 210, 215, 219, 240, 241, 

242, 243, 244, 245, 246, 475, 494 
stygius, horsefly, 239, 244, 245 
taeniatus, horsefly, 215, 217, 484, 493 
taeniola, horsefly, 237 
tergestinus, horsefly, 219 
trigeminus, horsefly, 211, 474 
trigonus, horsefly, 211, 474 



INDEX 



517 



Tabarms spp., tropicus, horsefly, 215, 494 

vagus, horsefly, 215, 494 

vivax, horsefly, 242 
Taenia cucumerina, tapeworm, 94 

nana (see Hymenolepis) 

(Taewiarhynchus) saginata, beef tape- 
worm, 120, 494 
Taeniidae, 120, 297, 355, 356 
Taeniorhynchus domesticus, mosquito, 70, 
82, 262, 480 

fuscopennatus, mosquito, 261, 479 
Tahaga, 217, 494 
Tapeworm, bovine, 494 

canine, 494 

fowl, 494, 495 

human, 494, 495 

rodent, 495 
Tapeworms (see Cestoda) 
Tarsonemidae, 404 
Tarsonemus intectus, mite, 404, 497 

uncinatus, mite, 404 
Teichomyza fusca, fly, 118 
Telosporidia, 219, 220, 355, 388, 420-422 
Temperature, 97-104 

and louse development, 304, 306, 307, 
309, 310 
Temperatures, absolute fatal, 98, 101 
Tenebrio molitor, granary beetle, 42, 54, 

55, 57, 60, 63, 78, 86, 486, 487, 495 
Tersesthes torrens, fly, 224 
Testudo mauritanica, turtle, 422, 475 
Tetanus, 373, 495 
Tetramitidae, 388 
Tetranychidae, 404 
Tetranychus molestissimus, mite, 404, 481 

telarius, mite, 474 

telarius russeolus, mite, 404 
Texas fever of cattle, 403, 414 
Thallophyta, 107-115, 209, 210, 211, 249, 

289, 290, 350, 351, 383-387, 392, 393 
Theileria spp., piroplasmids, 414 

parva, piroplasmid, 417, 478 
Thelohania ovata, protozoan, 120 
Thelohaniidae, 120, 388 
Theobaldia anwulata (see Culiseta) 
Theraphosa javanensis, spider, 464, 489 
Theridium lugubre, kara kist spider, 464, 
489 

13-guttatum, spider, 464, 489 
Thermalgesia, 100 
Thermanastas'is, 99 
Thermanesthesia, 98, 101 
Thermesthesia, 100 
Thermohyperesthesia, 100 
Thermonochelia, 98, 100 
Thermophilic, 100 
Thermophobia, 101 
Thermophylic, 100 
Thermoplegia, 98, 101 
Thermopnigia, 100 
Thermopolypnea, 100 
Thermopractic zone, 98, 99, 102 
Thermosystaltic, 101 
Thermotaxis, 101 



Thermotropism, 101 

Thorn-headed worms (see Acanthoceph- 

Three-day fever, 211 
Tick bite, 409 

bite fever, human, 410 

bite treatment, 448, 449 

control, 440-449 

dip, 442 

fever of Miana, 412 

fevers, 412 

paralysis (see Paralysis) 
Ticks, 403-429 
Tile drainage, 277, 278 
Tin can dumps, 282 
Toilet flushing box, 282 
Town, insanitary, 38 

sanitation, 38, 39 
Toxemia, 287, 288, 495 
Toxins, insect, 27 
Trachoma, 116, 122, 495 
Tragelaphus spekei, antelope, 215 
Train disinfection, 322 
Traps in sinks, 282 
Trash, 41 
Trematoda, flukes, 57, 58, 59, 81, 82, 83, 

88, 120, 121 
Trench fever, 48, 292, 293, 294, 312, 313, 

495 
Treponema pertenue, spirochaete, 119, 497 
Triatoma spp., kissing bugs, 414, 469 

chagasi, kissing bugs, 394, 476 

geniculata, kissing bugs, 394, 476 

infestans, kissing bugs, 393, 482 

megista, kissing bugs, 394, 399, 400 

rubro fas data, kissing bugs, 399, 400 

sanguisuga, kissing bugs, 400 

sorolida, kissing bugs, 394, 476 
Trichodectes canis (see T. latus) 

climax, goat louse, 346 

hermsi, goat louse, 346 

latus, dog louse, 53, 86, 297, 344, 355, 
494 

parumpilosus, horse louse, 347 

scalaris, cattle louse, 288, 322, 333 

sphaerocephalus, sheep louse, 346 

subrostratus, cat louse, 344 
Trichomonas orthopterum, protozoan, 388 
Trichoptera, caddice flies, 59, 83 
Trichosomidae, 122 

Trichuris trichiura, whipworm, 122, 497 
Trigona sp., honey bee, 22 

amalthea, honey bee, 468, 489 

bipunctata, honey bee, 468, 489 

limao, honey bee, 468, 489 

ruflcrus, honey bee, 468, 489 
Trochosa singoriensis, spider, 463, 489 
Trombidium akamushi (see Leptus) 

autumnalis, mite, 404, 477 

batatas, mite, 404, 477 

holosericeum, mite, 404, 477 

inop'matum, mite, 404, 477 

striaticeps, mite, 404, 477 
Troughs, water, 282 



518 



INDEX 



Trypanosoma sp., trypanosome, 214, 251, 
414 

spp. (see Castellanella, Duttonella, 
Schizotrypanum, Trypanozoon) 

Christopher si, trypanosome, 414 

franki, trypanosome, 218 

gallinarum, trypanosome, 218, 496 

grayi, trypanosome, 218, 496 

noctiiae, trypanosome, 251 

theileri, trypanosome, 218, 480 

tullochi, trypanosome, 218 

vespertilionis, trypanosome, 395, 495 

ziemanni, trypanosome, 251 
Trypanosomiasis, 49 

animal, 495 

bat, 395, 495 

bovine, 495, 496 

crocodile, 496 

equine, 496 

fowl, 496 

goat, 496 

ovine, 496 

rabbit, 496 

rat, 395 

rodent, 496 

simian, 496 
Trypanosomidae, 119, 214-218, 294, 352- 

354, 393-395, 414 
Trypanozoon blanchardi, trypanosome, 352, 
496 

duttoni, trypanosome, 352, 395, 496 

lewisi, trypanosome, 294, 352, 353, 395, 
496 

nabiasi, trypanosome, 353, 496 

rabinowitschi, trypanosome, 354, 496 
Tsetse fly (see Glossdna spp.) 
Tsutsugamushi disease, 413, 497 
Tuberculosis, 114, 115, 387, 497 
Tumbu fly (see Cordylobia anthropophaga) 
Tumors, 389 

sebaceous, 497 
Turkey, 408 

lice, 343 
Tydeus molestus, mite, 408, 481 
Tylenchus sp., worm, 89 
Typhoid fever, 49, 114, 115, 290, 291, 387, 

393 497 
Typhus' fever, 48, 291, 292, 312, 313, 497 
Tyroglyphidae, 405 

Tyroqlyphus longior castellanii, mite, 405, 
481 
siro, mite, 405, 497 

Urine soakage pit, 48 
Urticaria, 286, 497 



Urticariasis, 404, 497 
Uta, 219, 224, 497 

Vagabond's disease, 287 
Vanillismus, 405, 497 

Ver du Cayor (see Cordylobia anthropoph- 
aga) 
Vermicides, 318, 319 
Vermijelly, 316 
Vermin problem in armies, 45 
Verruga peruviana, 211, 226, 497 
Vertical drainage, 278 
Vespa spp., wasps, 468, 488 
Volhynian fever, 294, 497 
Vulpes vulpes atlantica, fox, 61 

Warbles, treatment, 204, 205 
Wart hog, 196 

Waste disposal in armies, 44-48 
Water beetles, 59, 86 

gates, 278, 279 

holes, 276 

pitchers, 282 
Weed-filled bays and lakes, 277 
Weep-holes, 277 
Weil's disease, 296 
Wells, 37 

Whipworm (see Trichuris trichiura) 
Withers, fistulous, 412, 497 
Wohlfahrtia magnifica, flesh fly, 175, 178, 

179, 180, 198, 480, 485 
Wolf nematode (see Spirocerca sanguino- 

lenta) 
Wood owl (see Syrnbum aluco) 
Wool blowflies, 181 
Worms, parasitic, 50-96 
Worry caused by insects, 20, 21 
Wound treatment for myiasis, 204 
Wristlet method of breeding lice, 303 
Wyoming intermittent fever, 497 

Xenopsylla cheopis, flea, 54, 56, 60, 80, 350, 
351, 352, 355, 357, 360, 474, 487, 488, 
495, 496 
cleopatrae, flea, 354, 355 
scopulifer, flea, 360, 366 
Xeranesthesia, 98, 101 
Xeronochelia, 98, 101 

Yaws, 119, 122, 497 

Yellow fever, 48, 259, 260, 262, 497 

Zero or effective temperature, 99 
Zousfana, 217 



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